android - MediaRecorder.stop() crashes the app - java

Everybody,
I'm trying to record audio.
The audio is record perfectly when record button is clicked.
I try to stop the record and the app crashing immediately after the stop button is clicked.
Can you please help me on fixing this code so i could continue building my project.
Here's part of the code:
public class window2 extends AppCompatActivity implements AdapterView.OnItemSelectedListener{
Spinner spinner;//choice between record and Speech-2-text.
Button play,stop,record;//record, stop and replay buttons.
String outputFile;//the record file.
MediaRecorder myAudioRecorder;//the record method.
int reRecord = 0;//reRecord value.
int pathVal = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_window2);
spinner = findViewById(R.id.spinner);
spinner.setOnItemSelectedListener(this);//upon change between record and S2T.
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor edit = sharedPreferences.edit();
if( sharedPreferences.getInt("pathVal",0) == 0)
edit.putInt("pathVal",1);
else {
pathVal = sharedPreferences.getInt("pathVal", pathVal);
edit.putInt("pathVal",pathVal+1);
}
pathVal = sharedPreferences.getInt("pathVal", 0);
edit.commit();
//3 buttons for record,stop and replay.
play = findViewById(R.id.button14);
stop = findViewById(R.id.button13);
record = findViewById(R.id.button11);
//to immune issues that may start if the buttons are enabled.
stop.setEnabled(false);
play.setEnabled(false);
//the file of recording.
outputFile = Environment.getExternalStorageDirectory().getAbsolutePath() + "/"+pathVal+".3gp";
//record settings.
myAudioRecorder = new MediaRecorder();
myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
myAudioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
myAudioRecorder.setOutputFile(outputFile);
//record button click.
record.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
play.setEnabled(false);
try{
//if we want to re record.
if(reRecord == 1)
{
//we build the settings again.
myAudioRecorder = new MediaRecorder();
myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
myAudioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
myAudioRecorder.setOutputFile(outputFile);
}
//prepare and start methods.
myAudioRecorder.prepare();
myAudioRecorder.start();
}catch (IllegalStateException ise) {
//something
}catch (IOException ioe){
//something
}
record.setEnabled(false);
stop.setEnabled(true);
Toast.makeText(window2.this, "Recording...", Toast.LENGTH_SHORT).show();
}
});
//stop button click.
stop.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
myAudioRecorder.stop();
myAudioRecorder.reset();
reRecord = 1;
myAudioRecorder = null;
record.setEnabled(true);
stop.setEnabled(false);
play.setEnabled(true);
Toast.makeText(window2.this, "Recorded!", Toast.LENGTH_SHORT).show();
}
});
play.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
MediaPlayer mediaPlayer = new MediaPlayer();
try {
mediaPlayer.setDataSource(outputFile);
mediaPlayer.prepare();
mediaPlayer.start();
Toast.makeText(window2.this, "Playing.", Toast.LENGTH_SHORT).show();
} catch (Exception e){
//something
}
}
});
}
public void OpenWindow4(View view)
{
Spinner spinner = findViewById(R.id.spinner3);
String SpinTxt = spinner.getSelectedItem().toString();
EditText edit2 = findViewById(R.id.editText);
String editTextTxt = edit2.getText().toString();
Intent intent = new Intent(this,window4.class);
intent.putExtra("THE_TEXT",editTextTxt);
intent.putExtra("SPIN_CHOICE",SpinTxt);
startActivity(intent);
}
public void OpenWindow4Speech(View view)
{
Spinner spinner = findViewById(R.id.spinner4);
String SpinTxt = spinner.getSelectedItem().toString();
EditText edit2 = findViewById(R.id.editText2);
String editTextTxt = edit2.getText().toString();
Intent intent = new Intent(this,window4.class);
intent.putExtra("THE_RECORD",outputFile);
intent.putExtra("SPIN_CHOICE",SpinTxt);
intent.putExtra("THE_TEXT",editTextTxt);
startActivity(intent);
}
#Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
String item = adapterView.getItemAtPosition(i).toString();
if (item.equals("S2T"))
{
Intent intent = new Intent(this,windows2B.class);
startActivity(intent);
}
}
#Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
}
and here is the logcat:
01-13 08:42:27.105 1031-1031/com.example.simplenigal.prealphabuilt V/MediaRecorder: prepare
01-13 08:42:27.105 1031-1031/com.example.simplenigal.prealphabuilt V/MediaRecorder: start
01-13 08:42:27.105 1031-1031/com.example.simplenigal.prealphabuilt E/MediaRecorder: start failed: -38
01-13 08:42:27.757 1031-1038/com.example.simplenigal.prealphabuilt I/art: Do partial code cache collection, code=115KB, data=106KB
01-13 08:42:27.757 1031-1038/com.example.simplenigal.prealphabuilt I/art: After code cache collection, code=115KB, data=106KB
01-13 08:42:27.757 1031-1038/com.example.simplenigal.prealphabuilt I/art: Increasing code cache capacity to 512KB
01-13 08:42:27.759 1031-1038/com.example.simplenigal.prealphabuilt I/art: Compiler allocated 6MB to compile void android.view.ViewRootImpl.performTraversals()
01-13 08:42:31.382 1031-1031/com.example.simplenigal.prealphabuilt I/ViewRootImpl: ViewRoot's Touch Event : ACTION_DOWN
01-13 08:42:31.452 1031-1031/com.example.simplenigal.prealphabuilt I/ViewRootImpl: ViewRoot's Touch Event : ACTION_UP
01-13 08:42:31.462 1031-1031/com.example.simplenigal.prealphabuilt V/MediaRecorder: stop
01-13 08:42:31.462 1031-1031/com.example.simplenigal.prealphabuilt E/MediaRecorder: stop called in an invalid state: 0
01-13 08:42:31.463 1031-1031/com.example.simplenigal.prealphabuilt D/AndroidRuntime: Shutting down VM
01-13 08:42:31.468 1031-1031/com.example.simplenigal.prealphabuilt E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.simplenigal.prealphabuilt, PID: 1031
java.lang.IllegalStateException
at android.media.MediaRecorder.native_stop(Native Method)
at android.media.MediaRecorder.stop(MediaRecorder.java:896)
at com.example.simplenigal.prealphabuilt.window2$2.onClick(window2.java:102)
at android.view.View.performClick(View.java:5624)
at android.view.View$PerformClick.run(View.java:22441)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6316)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:872)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:762)
thanks to every one who paying attention and helping.
Still looking for help

Related

Android NULL Pointer Exception and Fragment data transmission [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 5 years ago.
I am a beginner at android studio, I have a mission to redesign the app. I use the Fragment. But when I run my app, it has stopped and there is no error in my Gradle. I looked for many website to solve my question, but still have no idea.
I have some questions below.
How can I fix the java.lang.RuntimeException (NULL Pointer Exception) ?
09-30 02:59:56.574 17706-17706/? E/memtrack: Couldn't load memtrack module (No such file or directory)
09-30 02:59:56.574 17706-17706/? E/android.os.Debug: failed to load memtrack module: -2
09-30 02:59:56.996 17722-17722/? E/memtrack: Couldn't load memtrack module (No such file or directory)
09-30 02:59:56.996 17722-17722/? E/android.os.Debug: failed to load memtrack module: -2
09-30 02:59:57.090 17734-17734/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: tw.com.flag.parking22, PID: 17734
java.lang.RuntimeException: Unable to start activity ComponentInfo{tw.com.flag.parking22/tw.com.flag.parking22.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at tw.com.flag.parking22.MainActivity.init(MainActivity.java:102)
at tw.com.flag.parking22.MainActivity.onCreate(MainActivity.java:71)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
at android.app.ActivityThread.access$800(ActivityThread.java:151) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5254) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
09-30 02:59:57.211 1160-1160/? E/EGL_emulation: tid 1160: eglCreateSyncKHR(1865): error 0x3004 (EGL_BAD_ATTRIBUTE)
09-30 03:02:15.409 2159-19872/com.google.android.gms E/Herrevad: [350] RemoteReportsRefreshChimeraService.a: want to send authenticated request, but no Google account on device
09-30 03:02:15.445 1998-2721/com.google.android.gms.persistent E/SQLiteLog: (2067) abort at 31 in [INSERT INTO pending_ops(source,tag,requires_charging,target_package,source_version,required_network_type,flex_time,target_class,runtime,retry_strategy,last_runtime,period,task_type,job_id,user_
09-30 03:02:15.445 1998-2721/com.google.android.gms.persistent E/SQLiteDatabase: Error inserting source=4 tag=NetworkReportService requires_charging=0 target_package=com.google.android.gms source_version=11509000 required_network_type=2 flex_time=3600000 target_class=com.google.android.gms.common.stats.net.NetworkReportService runtime=1506742923454 retry_strategy={"maximum_backoff_seconds":{"3600":0},"initial_backoff_seconds":{"30":0},"retry_policy":{"0":0}} last_runtime=0 period=7200000 task_type=1 job_id=-1 user_id=0
android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: pending_ops.tag, pending_ops.target_class, pending_ops.target_package, pending_ops.user_id (code 2067)
at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:782)
at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1471)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1341)
at swi.a(:com.google.android.gms#11509280:208)
at sxo.a(:com.google.android.gms#11509280:64)
at sxp.handleMessage(:com.google.android.gms#11509280:29)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.os.HandlerThread.run(HandlerThread.java:61)
09-30 03:02:15.446 1998-2721/com.google.android.gms.persistent E/NetworkScheduler: Error persisting task: com.google.android.gms/.common.stats.net.NetworkReportService{u=0 tag="NetworkReportService" trigger=window{period=7200s,flex=3600s,earliest=5988s,latest=9588s} requirements=[NET_ANY] attributes=[PERSISTED,RECURRING] scheduled=2388s last_run=N/A jid=N/A status=PENDING retries=0}
09-30 03:02:15.474 1170-1578/? E/Drm: Failed to find drm plugin
09-30 03:02:15.563 2159-2680/com.google.android.gms E/Volley: [129] BasicNetwork.performRequest: Unexpected response code 307 for https://android.googleapis.com/nova/herrevad/network_quality_info
09-30 03:02:15.888 1998-2721/com.google.android.gms.persistent E/SQLiteLog: (2067) abort at 31 in [INSERT INTO pending_ops(source,tag,requires_charging,target_package,source_version,required_network_type,flex_time,target_class,runtime,retry_strategy,last_runtime,period,task_type,job_id,user_
09-30 03:02:15.888 1998-2721/com.google.android.gms.persistent E/SQLiteDatabase: Error inserting source=4 tag=AggregationTaskTag requires_charging=0 target_package=com.google.android.gms source_version=11509000 required_network_type=2 flex_time=600000 target_class=com.google.android.gms.checkin.EventLogService runtime=1506741123628 retry_strategy={"maximum_backoff_seconds":{"3600":0},"initial_backoff_seconds":{"30":0},"retry_policy":{"0":0}} last_runtime=0 period=1800000 task_type=1 job_id=-1 user_id=0
android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: pending_ops.tag, pending_ops.target_class, pending_ops.target_package, pending_ops.user_id (code 2067)
at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:782)
at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1471)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1341)
at swi.a(:com.google.android.gms#11509280:208)
at sxo.a(:com.google.android.gms#11509280:64)
at sxp.handleMessage(:com.google.android.gms#11509280:29)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.os.HandlerThread.run(HandlerThread.java:61)
09-30 03:02:15.888 1998-2721/com.google.android.gms.persistent E/NetworkScheduler: Error persisting task: com.google.android.gms/.checkin.EventLogService{u=0 tag="AggregationTaskTag" trigger=window{period=1800s,flex=600s,earliest=1787s,latest=2387s} requirements=[NET_ANY] attributes=[PERSISTED,RECURRING] scheduled=587s last_run=N/A jid=N/A status=PENDING retries=0}
09-30 03:03:37.417 1170-1578/? E/audio_hw_generic: Error opening input stream format 1, channel_mask 0010, sample_rate 16000
09-30 03:30:15.406 2159-21157/com.google.android.gms E/Herrevad: [355] RemoteReportsRefreshChimeraService.a: want to send authenticated request, but no Google account on device
09-30 03:30:15.511 2159-21162/com.google.android.gms E/ZappConnFactory: Unable to bind to PlayStore
09-30 03:30:15.518 2159-21168/com.google.android.gms E/ZappLogOperation: Unable to bind to Phonesky
09-30 03:30:15.526 2159-21162/com.google.android.gms E/ZappConnFactory: Unable to bind to PlayStore
09-30 03:30:15.526 2159-21162/com.google.android.gms E/ZappConnFactory: Unable to bind to PlayStore
09-30 03:30:15.551 2159-2678/com.google.android.gms E/Volley: [127] BasicNetwork.performRequest: Unexpected response code 307 for https://android.googleapis.com/nova/herrevad/network_quality_info
09-30 03:30:15.572 1170-1578/? E/Drm: Failed to find drm plugin
09-30 03:30:22.524 2159-2159/com.google.android.gms E/ActivityThread: Service com.google.android.gms.chimera.GmsIntentOperationService has leaked ServiceConnection ctn#2f714ea6 that was originally bound here
android.app.ServiceConnectionLeaked: Service com.google.android.gms.chimera.GmsIntentOperationService has leaked ServiceConnection ctn#2f714ea6 that was originally bound here
at android.app.LoadedApk$ServiceDispatcher.<init>(LoadedApk.java:1077)
at android.app.LoadedApk.getServiceDispatcher(LoadedApk.java:971)
at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1774)
at android.app.ContextImpl.bindService(ContextImpl.java:1757)
at android.content.ContextWrapper.bindService(ContextWrapper.java:539)
at android.content.ContextWrapper.bindService(ContextWrapper.java:539)
at android.content.ContextWrapper.bindService(ContextWrapper.java:539)
at android.content.ContextWrapper.bindService(ContextWrapper.java:539)
at com.google.android.gms.chimera.container.zapp.ZappLogOperation.onHandleIntent(:com.google.android.gms#11509280:1)
at com.google.android.chimera.IntentOperation.onHandleIntent(:com.google.android.gms#11509280:2)
at bwy.run(:com.google.android.gms#11509280:10)
at bwv.run(:com.google.android.gms#11509280:14)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
09-30 03:44:15.607 1998-2721/com.google.android.gms.persistent E/SQLiteLog: (2067) abort at 31 in [INSERT INTO pending_ops(source,tag,requires_charging,target_package,source_version,required_network_type,flex_time,target_class,runtime,retry_strategy,last_runtime,period,task_type,job_id,user_
09-30 03:44:15.607 1998-2721/com.google.android.gms.persistent E/SQLiteDatabase: Error inserting source=4 tag=AggregationTaskTag requires_charging=0 target_package=com.google.android.gms source_version=11509000 required_network_type=2 flex_time=600000 target_class=com.google.android.gms.checkin.EventLogService runtime=1506743055606 retry_strategy={"maximum_backoff_seconds":{"3600":0},"initial_backoff_seconds":{"30":0},"retry_policy":{"0":0}} last_runtime=0 period=1800000 task_type=1 job_id=-1 user_id=0
android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: pending_ops.tag, pending_ops.target_class, pending_ops.target_package, pending_ops.user_id (code 2067)
at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:782)
at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1471)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1341)
at swi.a(:com.google.android.gms#11509280:208)
at sxo.a(:com.google.android.gms#11509280:64)
at sxp.handleMessage(:com.google.android.gms#11509280:29)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.os.HandlerThread.run(HandlerThread.java:61)
09-30 03:44:15.607 1998-2721/com.google.android.gms.persistent E/NetworkScheduler: Error persisting task: com.google.android.gms/.checkin.EventLogService{u=0 tag="AggregationTaskTag" trigger=window{period=1800s,flex=600s,earliest=1199s,latest=1799s} requirements=[NET_ANY] attributes=[PERSISTED,RECURRING] scheduled=0s last_run=N/A jid=N/A status=PENDING retries=0}
09-30 03:44:15.637 2159-21184/com.google.android.gms E/Herrevad: [371] RemoteReportsRefreshChimeraService.a: want to send authenticated request, but no Google account on device
09-30 03:44:15.755 2159-2676/com.google.android.gms E/Volley: [126] BasicNetwork.performRequest: Unexpected response code 307 for https://android.googleapis.com/nova/herrevad/network_quality_info
09-30 03:46:13.425 1171-1171/? E/installd: eof
09-30 03:46:13.425 1171-1171/? E/installd: failed to read size
Here is the main activity code
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager =(ViewPager) findViewById(R.id.pager);
PagerAdapter padapter = new PagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(padapter);
//--------------------------------------------------------------------
init();
Action();
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
if(newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
}
else {
}
}
private void init(){
System.out.println("start---------------------");
textView_userIDVal = (TextView) findViewById(R.id.textView_userIDVal);
textView_parkingNoVal = (TextView) findViewById(R.id.textView_parkingNoVal);
textView_pillarNoVal = (TextView) findViewById(R.id.textView_pillarNoVal);
textView_colorVal = (TextView) findViewById(R.id.textView_colorVal);
imageView = (ImageView) findViewById(R.id.imageView);
button_space = (Button) findViewById(R.id.button_space);
button_scan = (Button) findViewById(R.id.button_scan);
button_find = (Button) findViewById(R.id.button_find);
simpleDateFormat = new SimpleDateFormat("MM/dd 'at' HH");
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
userID = Build.SERIAL;
//-------------error start next----------------
textView_userIDVal.setText("User ID : " + userID);
}
if(ContextCompat.checkSelfPermission(this, android.Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.CAMERA}, 200);
}
sharedPreferences = getSharedPreferences("Data", 0);
if(sharedPreferences.contains("parkingNum") && sharedPreferences.contains("time")) {
parkingNumtmp = sharedPreferences.getString("parkingNum", "");
textView_parkingNoVal.setText("Parking No. : " + parkingNumtmp + "\t(" + sharedPreferences.getString("time", "") + ")");
}
builder = new AlertDialog.Builder(this);
builder.setCancelable(false);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
}
});
builder_timeout = new AlertDialog.Builder(this);
builder_timeout.setTitle("REMIND");
builder_timeout.setMessage("Do you find your car ?");
builder_timeout.setCancelable(false);
builder_timeout.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
try {
json_data = new JSONObject();
json_data.put("MT", "timeout");
json_data.put("PlaceMac", parkingNumtmp);
json_data.put("UserMac", userID);
json_write = new JSONObject();
json_write.put("Data", json_data);
json_write.put("Read", false);
isCloseScreen = false;
} catch (JSONException e) {
e.printStackTrace();
}
thread = new Thread(TCP);
thread.start();
timer_count = 0;
startFlag = false;
}
});
builder_timeout.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
maxTime = 10;
maxTime = maxTime / 2;
timer_count = 0;
startFlag = true;
}
});
}
private void Action(){
button_space.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
json_data = new JSONObject();
json_data.put("MT", "count");
json_write = new JSONObject();
json_write.put("Data", json_data);
json_write.put("Read", true);
//System.out.println(json_write + "\n");
} catch (JSONException e) {
e.printStackTrace();
}
thread = new Thread(TCP);
thread.start();
/*builder.setTitle("INFORMATION");
builder.setMessage("All : " + "\nNow : " );
AlertDialog alertDialog = builder.create();
alertDialog.show();*/
}
});
button_scan.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, ScanActivity.class);
startActivityForResult(intent, REQUEST_CODE);
}
});
button_find.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(parkingNumtmp != null) {
try {
maxTime = 10;
json_data = new JSONObject();
json_data.put("MT", "search");
json_data.put("PlaceMac", parkingNumtmp);
json_data.put("UserMac", userID);
json_write = new JSONObject();
json_write.put("Data", json_data);
json_write.put("Read", true);
//System.out.println(json_write + "\n");
} catch (JSONException e) {
e.printStackTrace();
}
Toast.makeText(getApplicationContext(), "Don't close the screen before you find your car ! ", Toast.LENGTH_LONG).show();
thread = new Thread(TCP);
thread.start();
}
else {
builder.setTitle("WARNING");
builder.setMessage("Please scan QRcode first!");
AlertDialog alertDialog = builder.create();
alertDialog.show();
}
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
if(data != null) {
final Barcode barcode = data.getParcelableExtra("barcode");
parkingNumtmp = barcode.displayValue;
Date date = new Date();
final String time = simpleDateFormat.format(date);
sharedPreferences.edit().putString("parkingNum", parkingNumtmp).putString("time", time).commit();
textView_parkingNoVal.post(new Runnable() {
#Override
public void run() {
textView_parkingNoVal.setText("Parking No. : " + parkingNumtmp + "\t(" + time +")");
}
});
}
}
}
About Fragment. Is there any setting I have to do when I receive data form sever?
I want to put the received data to TextView in the another view .

Your init() function is probably try to find views inside fragments in view pager. However, at that moment, the fragments are not inflated yet, so your views in the activity are null and trying to do operation on them gives NPE. You should use onCreateView() of Fragment classes to find those views. Then you may notify main activity via callback mechanism.
For example, create FirstFragment as follows:
public class FirstFragment extends Fragment {
private OnFirstFragmentReadyListener callback;
#Override
public void onAttach(Context context) {
super.onAttach(context);
// This makes sure that the container activity has implemented the callback.
try {
callback = (OnFirstFragmentReadyListener) context;
} catch (ClassCastException e) {
throw new ClassCastException(context.toString()
+ " must implement OnFirstFragmentReadyListener");
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_first, container, false);
return rootView;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Notify the parent activity that the fragment is inflated.
callback.onFirstFragmentReady();
}
public interface OnFirstFragmentReadyListener {
void onFirstFragmentReady();
}
}
Let the layout of FirstFragment as follows (referenced above as fragment_first):
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/first_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
Assume we created two more similar fragment classes named as SecondFragment and ThirdFragment. Then the activity should be like this:
public class MainActivity extends AppCompatActivity implements FirstFragment.OnFirstFragmentReadyListener,
SecondFragment.OnSecondFragmentReadyListener, ThirdFragment.OnThirdFragmentReadyListener {
...
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager =(ViewPager) findViewById(R.id.pager);
PagerAdapter pagerAdapter = new PagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(pagerAdapter);
// Don't call these functions here, spread them into callbacks.
// init();
// Action();
}
#Override
public void onFirstFragmentReady() {
TextView firstTextView = (TextView) findViewById(R.id.first_label);
...
// Now you have the views from FirstFragment instance.
// You can now call setText() or setOnClickListener() here.
}
#Override
public void onSecondFragmentReady() {
TextView secondTextView = (TextView) findViewById(R.id.second_label);
...
// Now you have the views from SecondFragment instance.
// You can now call setText() or setOnClickListener() here.
}
#Override
public void onThirdFragmentReady() {
TextView thirdTextView = (TextView) findViewById(R.id.third_label);
...
// Now you have the views from ThirdFragment instance.
// You can now call setText() or setOnClickListener() here.
}
}
Although this code works, this may not be the best way. I think it is better to do operations on views like setting texts or assigning OnClickListeners in fragments itself. If you need to notify a fragment after an action happened in the parent activity, you can implement public methods inside fragments and you can call them from the parent activity when needed.

In fragment you should call the function in onCreateView function(reason as mention by #Mehmed) which is something like below:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.your_fragment, container, false);
//all findViewById;
TextView yourTextView = (Text)view.findViewById(R.id.yourTextView);
//here call for your function
init();
// any other function goes here
return view;
}

What exactly is causing this NullPointerException? [duplicate]

This question already has answers here:
Android: NullPointerException Working With SharedPreferences
(3 answers)
Closed 7 years ago.
I'm pretty new to Android development and am currently working on an app which is supposed to save the current time and date when a button is pressed, store it to SharedPreferences and then present the String when a different button is pressed. I got it working but did some tinkering today and now I'm getting a NullPointerException that I can't solve, even after having spent about 45 minutes on Google and Stackoverflow trying different code fragments. Can anyone who is better at this than me tell me what I'm missing?
Here is the relevant code:
public class GetTimeStamp extends AppCompatActivity {
private String date;
public void setDate (View view){
DateFormat df = new SimpleDateFormat("dd.MM.yyy 'om' HH:mm");
date = df.format(Calendar.getInstance().getTime());
}
public String getDate(){
return date;
}
SharedPreferences prefs = this.getSharedPreferences("SharedPrefs", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_get_time_stamp);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fabSaveTimeStamp);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
setDate(view);
editor.putString("storedDate", date);
editor.commit();
Toast.makeText(getBaseContext(), "blablabla", Toast.LENGTH_SHORT).show();
}
})
FloatingActionButton fab3 = (FloatingActionButton) findViewById(R.id.fabShowTimeStamp);
fab3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//retrieve the date from SharedPreferences and store it to a local String
String retrievedDate = prefs.getString("storedDate", null);
if (retrievedDate!=null){
AlertDialog alertDialog = new AlertDialog.Builder(GetTimeStamp.this).create(); //Read Update
alertDialog.setTitle("");
alertDialog.setMessage("somemessage" + retrievedDate);
alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
});
alertDialog.show();
}else {
//create an alert dialog explaining to the user that no date has been saved yet
AlertDialog alertDialog = new AlertDialog.Builder(GetTimeStamp.this).create(); //Read Update
alertDialog.setTitle("Error");
alertDialog.setMessage("errorexplanation");
alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
});
alertDialog.show();
}
}
});
And here are the errors:
02-08 22:49:36.142 19735-19735/? W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x41ed7ce0)
02-08 22:49:36.152 19735-19735/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.user.appname, PID: 19735
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.user.appname/com.example.user.appname.GetTimeStamp}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2131)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2264)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1205)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5139)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:796)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:612)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:173)
at com.example.user.appname.GetTimeStamp.<init>(GetTimeStamp.java:36)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1208)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2122)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2264) 
at android.app.ActivityThread.access$800(ActivityThread.java:144) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1205) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:136) 
at android.app.ActivityThread.main(ActivityThread.java:5139) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:796) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:612) 
at dalvik.system.NativeStart.main(Native Method) 

You are trying to initialize the following class field before you are allowed to:
SharedPreferences prefs = this.getSharedPreferences("SharedPrefs", Context.MODE_PRIVATE);
Only declare the field:
SharedPreferences prefs;
and then assign it in your onCreate() method:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
prefs = getSharedPreferences("SharedPrefs", Context.MODE_PRIVATE);
...
}

Unable to modify values in ListView

I'm faced with this problem
java.lang.UnsupportedOperationException
What I want to do is easy, I'll show you an example.
MyList
Blue
Red
Green
When I make an OnItemLongClickListener() for example on Green, my list should looks like :
MyList
Green
What I've tried is
final ArrayAdapter < String > adapter = new ArrayAdapter < String > (getActivity(), android.R.layout.simple_list_item_1, FileBackup.getFilesFound());
adapter.setNotifyOnChange(true);
lv.setAdapter(adapter);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView <? > arg0, View arg1, final int arg2, long arg3) {
String itemValue = (String) lv.getItemAtPosition(arg2);
Log.d("Item clicked --> ", lv.getItemAtPosition(arg2).toString());
FileBackup.setNameFile(itemValue);
final Dialog dialog = new Dialog(getActivity());
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.user_file_choose);
Button button = (Button) dialog.findViewById(R.id.btOk);
Button button2 = (Button) dialog.findViewById(R.id.btKo);
TextView tvBackUpFile = (TextView) dialog.findViewById(R.id.textViewContentDialog);
tvBackUpFile.setText("Do you want to backup " + FileBackup.getNameFile() + " ?");
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
dialog.dismiss();
//Clear all the ListView
lv.setAdapter(null);
}
});
}
});
It's working fine, if I want to clear the ListView, but in my case I DON'T WANT TO, I tried to add item or remove with :
adapter.addAll("Something");
or
lv.removeViewAt(2);
And then call adapter.notifyDataSetChanged(); but it gives the same error every time I try to.
What I'm doing wrong?
EDIT
Now the code looks like :
final ArrayAdapter < String > adapter = new ArrayAdapter < String > (getActivity(), Arrays.asList(FileBackup.getFilesFound()));
adapter.setNotifyOnChange(true);
lv.setAdapter(adapter);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView <? > arg0, View arg1, final int arg2, long arg3) {
String itemValue = (String) lv.getItemAtPosition(arg2);
Log.d("Item clicked --> ", lv.getItemAtPosition(arg2).toString());
FileBackup.setNameFile(itemValue);
final Dialog dialog = new Dialog(getActivity());
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.user_file_choose);
Button button = (Button) dialog.findViewById(R.id.btOk);
Button button2 = (Button) dialog.findViewById(R.id.btKo);
TextView tvBackUpFile = (TextView) dialog.findViewById(R.id.textViewContentDialog);
tvBackUpFile.setText("Do you want to backup " + FileBackup.getNameFile() + " ?");
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
dialog.dismiss();
//Clear all the ListView
lv.setAdapter(null);
//Trying to add that current item clicked
adapter.addAll(FileBackup.getNameFile());
adapter.notifyDataSetChanged();
}
});
}
});
And this is the LogCat error :
06-10 20:14:43.531 8072-8072/info.androidhive.tabsswipe E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: info.androidhive.tabsswipe, PID: 8072
java.lang.UnsupportedOperationException
at java.util.AbstractList.add(AbstractList.java:404)
at java.util.AbstractList.add(AbstractList.java:425)
at java.util.Collections.addAll(Collections.java:2583)
at android.widget.ArrayAdapter.addAll(ArrayAdapter.java:211)
at info.androidhive.tabsswipe.BackupWA$1$1.onClick(BackupWA.java:80)
at android.view.View.performClick(View.java:4456)
at android.view.View$PerformClick.run(View.java:18462)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5102)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Where it's pointing this --> adapter.addAll(FileBackup.getNameFile()); but it's not null I also tried to adapter.addAll("RED");
EDIT2
I'm trying to keep the name what I've clicked to FileBackup.getFilesFound() so I can create my adapter again I'm doing it with :
String[] itemvalues = (String[]) lv.getItemAtPosition(arg2);
FileBackup.setFilesFound(itemvalues);
And then I'm doing :
adapter.addAll(Arrays.asList(FileBackup.getFilesFound()));
//Add the name
adapter.notifyDataSetChanged();
On my class is declared as String[] and the error is :
java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.String[]
EDIT3
It's giving the same error every time I want to update the list... #Y.S. said that It's better to post all of my code to see what's going on, because somewhere I'm using String[] instead of ArrayList<String>
That's my FileBackup.java
public class FileBackup {
private String path;
private String pathFile;
private File FileToBackUp;
private String SDpath;
private String[] FilesFound;
private String nameFile;
public String getPathFile() {
return pathFile;
}
public void setPathFile(String pathFile) {
this.pathFile = pathFile;
}
public String getNameFile() {
return nameFile;
}
public void setNameFile(String nameFile) {
this.nameFile = nameFile;
}
public FileBackup(String path){
this.path = path;
}
public File getFileToBackUp() {
return FileToBackUp;
}
public void setFileToBackUp(File fileToBackUp) {
FileToBackUp = fileToBackUp;
}
public String[] getFilesFound() {
this.FilesFound = FilesFound();
return FilesFound;
}
public String[] FilesFound() {
File dir = new File(this.path);
File[] filelist = dir.listFiles();
String[] theNamesOfFiles = new String[filelist.length];
for (int i = 0; i < theNamesOfFiles.length; i++) {
theNamesOfFiles[i] = filelist[i].getName();
}
return theNamesOfFiles;
}
And this is how I have the List of the files.
final String itemValue = (String) lv.getItemAtPosition(arg2);
Log.d("Item clicked --> ", lv.getItemAtPosition(arg2).toString());
final Dialog dialog = new Dialog(getActivity());
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.user_file_choose);
Button button = (Button) dialog.findViewById(R.id.btOk);
Button button2 = (Button) dialog.findViewById(R.id.btKo);
FileBackup.setNameFile(itemValue);
TextView tvBackUpFile = (TextView) dialog.findViewById(R.id.textViewContentDialog);
tvBackUpFile.setText("Do you want to backup " + FileBackup.getNameFile() + " ?");
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
//The complete path of the fail
FileBackup.setPathFile(GlobalConstant.path + "/" + FileBackup.getNameFile());
//Converting the path of the file to a File and putting it to FileToBackUp
FileBackup.setFileToBackUp(PathToFile(FileBackup.getPathFile()));
dialog.dismiss();
//Clear all the ListView
lv.setAdapter(null);
//Add the name
BackUpFile.setEnabled(true);
}
});
I tried to do something like :
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
//The complete path of the fail
FileBackup.setPathFile(GlobalConstant.path + "/" + FileBackup.getNameFile());
//Converting the path of the file to a File and putting it to FileToBackUp
FileBackup.setFileToBackUp(PathToFile(FileBackup.getPathFile()));
///// THIS IS NEW ///////////
String itemvalues = (String) lv.getItemAtPosition(arg2);
FileBackup.setFilesFound(new String[] {
itemvalues
});
adapter.addAll(FileBackup.getFilesFound());
//Add the name
adapter.notifyDataSetChanged();
//////////TIL HERE/////////////
dialog.dismiss();
//Clear all the ListView
//Add the name
BackUpFile.setEnabled(true);
}
});
And this is the LogCat
java.lang.UnsupportedOperationException
at java.util.AbstractList.add(AbstractList.java:404)
at java.util.AbstractList.add(AbstractList.java:425)
at java.util.AbstractCollection.addAll(AbstractCollection.java:76)
at android.widget.ArrayAdapter.addAll(ArrayAdapter.java:195)
at info.androidhive.tabsswipe.BackupWA$1$1.onClick(BackupWA.java:88)
at android.view.View.performClick(View.java:4456)
at android.view.View$PerformClick.run(View.java:18462)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5102)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Where is pointing
adapter.addAll(Arrays.asList(FileBackup.getFilesFound()));
Also I've tried with
adapter.addAll(FileBackup.getFilesFound());
But it's giving the same error... Maybe is that I'm doing this on a not correct place...

Look this answer:
ArrayAdapter
So basically as in this answer said: "The ArrayAdapter, on being initialized by an array, converts the array into a AbstractList (List) which cannot be modified."
So it easy, create your own ArrayList, in your case of type String, and then assign this to CustomAdapter, then you can just remove items from your ArrayList and notifyDataSetChanged() should works.
Regards

Android: No Activity found to handle Intent (trying to add an activity to exsisting app)

Ok so I am very new to the Android programming, I am starting week 2 of this class and cannot for the life of me figure out what is going wrong. I have read/watched tons of tutorials on adding new Activities and nothing works.
Assignment: Use the Activities app and add a fourth activity
My activity is simple, 3 buttons and an image. One button makes the image visible and the other makes it invisible. Third returns back to the main.
Note: I edited the original app to have buttons on Main Activity because it had me hitting center on the d-pad which I found dumb. Another note is that Activity 2 & 3 use the same layout and do basically the same thing from what I can tell
public class MainActivity extends Activity {
String tag = "Events";
int request_Code = 1;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//---hides the title bar---
//requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
Log.d(tag, "In the onCreate() event");
Button act2Butt = (Button) findViewById(R.id.act2Butt);
Button act3Butt = (Button) findViewById(R.id.act3Butt);
Button act4Butt = (Button) findViewById(R.id.act4Butt);
act2Butt.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
startActivityForResult(new Intent("net.learn2develop.ACTIVITY2"), request_Code);
}
});
act3Butt.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
startActivityForResult(new Intent("net.learn2develop.ACTIVITY2"), request_Code);
}
});
act4Butt.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
startActivityForResult(new Intent("net.learn2develop.MYACTIVITY"), request_Code);
}
});
}
/*
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER)
{
//startActivity(new Intent("net.learn2develop.ACTIVITY2"));
//startActivity(new Intent(this, Activity2.class));
startActivityForResult(new Intent(
"net.learn2develop.ACTIVITY2"),
request_Code);
}
return false;
}
*/
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
if (requestCode == request_Code) {
if (resultCode == RESULT_OK) {
Toast.makeText(this,data.getData().toString(),
Toast.LENGTH_LONG).show();
}
}
}
public void onStart()
{
super.onStart();
Log.d(tag, "In the onStart() event");
}
public void onRestart()
{
super.onRestart();
Log.d(tag, "In the onRestart() event");
}
public void onResume()
{
super.onResume();
Log.d(tag, "In the onResume() event");
}
public void onPause()
{
super.onPause();
Log.d(tag, "In the onPause() event");
}
public void onStop()
{
super.onStop();
Log.d(tag, "In the onStop() event");
}
public void onDestroy()
{
super.onDestroy();
Log.d(tag, "In the onDestroy() event");
}
public class MyActivity extends Activity{
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity4);
Button yesButt = (Button) findViewById(R.id.yesButton);
Button noButt = (Button) findViewById(R.id.noButton);
Button finButt = (Button) findViewById(R.id.finButton);
final ImageView img1 = (ImageView) findViewById(R.id.image1);
yesButt.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
img1.setVisibility(View.VISIBLE);
}
});
noButt.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
img1.setVisibility(View.INVISIBLE);
}
});
finButt.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent data = new Intent();
data.setData(Uri.parse("OMG IT WORKS"));
setResult(RESULT_OK, data);
finish();
}
});
}
public class Activity2 extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity2);
String defaultName="";
Bundle extras = getIntent().getExtras();
if (extras!=null)
{
defaultName = extras.getString("Name");
}
//---get the EditText view---
EditText txt_username =
(EditText) findViewById(R.id.txt_username);
txt_username.setHint(defaultName);
//---get the OK button---
Button btn = (Button) findViewById(R.id.btn_OK);
//---event handler for the OK button---
btn.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view) {
Intent data = new Intent();
//---get the EditText view---
EditText txt_username =
(EditText) findViewById(R.id.txt_username);
//---set the data to pass back---
data.setData(Uri.parse(
txt_username.getText().toString()));
setResult(RESULT_OK, data);
//---closes the activity---
finish();
}
});
}
I have entered the code for Main Activity, My Activity (the one I made), and Activity 2. My Activity runs great and does exactly what I want it to but if I try to access it from main it dies.
928-928/net.learn2develop.Activities E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: net.learn2develop.Activities, PID: 928
android.content.ActivityNotFoundException: No Activity found to handle Intent { act=net.learn2develop.MYACTIVITY }
at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1765)
at android.app.Instrumentation.execStartActivity(Instrumentation.java:1485)
at android.app.Activity.startActivityForResult(Activity.java:3736)
at android.app.Activity.startActivityForResult(Activity.java:3697)
at net.learn2develop.Activities.MainActivity$3.onClick(MainActivity.java:48)
at android.view.View.performClick(View.java:4756)
at android.view.View$PerformClick.run(View.java:19749)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
This code is for my last attempt and making it work before throwing my hands up. Last thing I did was make My Activity act like the other and use startActivityForResult.
Any help would help greatly. I don't know if it matters or not but I do not have a .class for My Activity in the bin directory but there is one for all the others.
If you need any more info please just ask.
Like I said before I'm really new to the whole Android area.
Edit: Manifest
<activity android:name=".MyActivity"
android:label="My Activity">
<intent-filter>
<action android:name="net.learn2develop.MYACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>

You may need to add the Activity to the manifest. If you are sure you have done this, I would recommend using an Intent slightly differently.
Try using an Intent the following way:
Intent intent = new Intent(MyActivity.this, SecondActivity.class);
startActivityForResult(intent, requestCode);
The first parameter of this Intent is the current Activity. The second parameter is theActivity you wish to navigate to. Handling an Intent this way prevents a small typo in the package name which would throw that exception. As long as the Activity you are trying to navigate to is in the manifest and you have set up your Intent like the code above, everything should work fine.
Good luck and happy coding!

you need to add your activity to your manifest
<activity
android:name=".MySecondActivity"
android:label="#string/title_second_activity">
</activity>

net.learn2develop.MYACTIVITY
Android is not finiding the above activity like other engineers said,add this activity in your manifest file so JVM can find which class you are referring to.

Updating Listview ( SharedPreferences -> ArrayList) from separate Class

I would like to update my Listview in a fragmen in a onPostExecute() separate class.
The first initialization of the the Listview doas work, but wehe I call createList() again, the App crashes (NullPointerException)
Any Idea?
Main_Fragment:
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View fragmentView = inflater.inflate(R.layout.main_fragment, container, false);
StartSocketService = (Button) fragmentView.findViewById(R.id.start_socketservice);
StartSocketService.setOnClickListener(this);
StopSocketService = (Button) fragmentView.findViewById(R.id.stop_socketservice);
StopSocketService.setOnClickListener(this);
listview = (ListView) fragmentView.findViewById(R.id.listView1);
createList();
return fragmentView;
}
public void createList(){
//Reading Server IPs from SharedPreferences and put them to ListView
SharedPreferences settings = getActivity().getSharedPreferences("Found_Devices", 0);
for (int i = 0; i < 255; i++) {
if ((settings.getString("Server"+i,null)) != null) {
serverList.add(settings.getString("Server"+i, null));
Log.v("Reading IP: " +settings.getString("Server"+i, null), " from SraredPreferrences at pos.: "+i );
}
}
//Initializing listView
final StableArrayAdapter adapter = new StableArrayAdapter(getActivity(),android.R.layout.simple_list_item_1, serverList);
listview.setAdapter(adapter);
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#TargetApi(Build.VERSION_CODES.JELLY_BEAN)
#Override
public void onItemClick(AdapterView<?> parent, final View view, int position, long id) {
final String item = (String) parent.getItemAtPosition(position);
view.animate().setDuration(2000).alpha(0).withEndAction(new Runnable() {
#Override
public void run() {
serverList.remove(item);
adapter.notifyDataSetChanged();
view.setAlpha(1);
}
});
}
});
}
Some class:
async_cient = new AsyncTask<Void, Void, Void>() {
...
protected void onPostExecute(Void result) {
Toast.makeText(mContext, "Scan Finished", Toast.LENGTH_SHORT).show();
Main_Fragment cList = new Main_Fragment();
cList.createList();
super.onPostExecute(result);
}
};
Log:
07-29 14:42:46.428 3382-3382/de.liquidbeam.LED.control D/AndroidRuntime﹕ Shutting down VM
07-29 14:42:46.428 3382-3382/de.liquidbeam.LED.control W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41549ba8)
07-29 14:42:46.438 3382-3382/de.liquidbeam.LED.control E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: de.liquidbeam.LED.control, PID: 3382
java.lang.NullPointerException
at de.liquidbeam.LED.control.fragments.Main_Fragment.createList(Main_Fragment.java:56)
at de.liquidbeam.LED.control.background.UDP_Discover$1.onPostExecute(UDP_Discover.java:94)
at de.liquidbeam.LED.control.background.UDP_Discover$1.onPostExecute(UDP_Discover.java:57)
at android.os.AsyncTask.finish(AsyncTask.java:632)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
07-29 14:47:46.591 3382-3382/de.liquidbeam.LED.control I/Process﹕ Sending signal. PID: 3382 SIG: 9
Lines:
56 : SharedPreferences settings = getActivity().getSharedPreferences("Found_Devices", 0);
94 : cList.createList();
57: async_cient = new AsyncTask<Void, Void, Void>() {

You creating a new instance of your fragment with no context (activity) to run in. So
the line
SharedPreferences settings = getActivity().getSharedPreferences("Found_Devices", 0);
Tries to get his activity but there is no activity where the fragment lives in ;)

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