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;
}
I am trying to create an android app on android studio which scans WIFI signals, and passes all the WIFI signal SSIDs containing "WDT_" to another intent.
When I run the app, it crashes due to a NPE.
I debugged the app, and it says that intent.getStringArrayExtra() in MultipleWifi.java is null.
Am I doing something wrong with passing the string array?
MainActivity.java:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WifiManager wifiManager = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);
WifiConfiguration conf = new WifiConfiguration();
int WDTWifiCount = 0;
List<ScanResult> results = wifiManager.getScanResults();
for (ScanResult scanResult : results) {
if (scanResult.SSID.contains("WDT_")) {
SSIDString[0] = (scanResult.SSID);
WDTWifiCount++;
}
}
WDTWifiCount = 2;
SSIDString[0] = "WDT_12345";
SSIDString[1] = "WDT_14445";
if (WDTWifiCount < 1) {
startActivity(new Intent(this, NoWifi.class));
} else if (WDTWifiCount > 1) {
Intent intent = new Intent(this, MultipleWifi.class);
intent.putExtra("SSIDList", SSIDString);
startActivityForResult(intent, 1);
}
conf.SSID = "\"" + networkSSID + "\"";
conf.preSharedKey = "\"" + networkPass + "\"";
WDTWifiCount = 0;
wifiManager.addNetwork(conf);
List<WifiConfiguration> list = wifiManager.getConfiguredNetworks();
for (WifiConfiguration i : list) {
if (i.SSID != null && i.SSID.equals("\"" + networkSSID + "\"") && WDTWifiCount != 0) {
wifiManager.disconnect();
wifiManager.enableNetwork(i.networkId, true);
wifiManager.reconnect();
break;
}
}
myWebView = new WebView(this);
myWebView.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
});
WebSettings webSettings = myWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setLoadWithOverviewMode(true);
webSettings.setUseWideViewPort(true);
webSettings.setSupportZoom(true);
webSettings.setBuiltInZoomControls(true);
myWebView.setWebChromeClient(new WebChromeClient());
myWebView.loadUrl("http://192.168.1.1/index.html");
}
MultipleWifi.java:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.multiplewifi);
Intent intent = getIntent();
final String[] StringSSID = intent.getStringArrayExtra("SSIDstring");
List<String> SSIDList = new ArrayList<String>(Arrays.asList(StringSSID));
final Spinner spinner = (Spinner) findViewById(R.id.spinner);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, SSIDList);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String SSID = spinner.getSelectedItem().toString();
Intent intent = new Intent();
intent.putExtra("SSID", SSID);
setResult(RESULT_OK, intent);
finish();
}
});
}
Debug:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.wdt, PID: 9031
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.wdt/com.example.wdt.MultipleWifi}: java.lang.NullPointerException: storage == null
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2200)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2250)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5105)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException: storage == null
at java.util.Arrays$ArrayList.<init>(Arrays.java:38)
at java.util.Arrays.asList(Arrays.java:155)
at com.example.wdt.MultipleWifi.onCreate(MultipleWifi.java:23)
at android.app.Activity.performCreate(Activity.java:5275)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2164)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2250)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5105)
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:792)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
at dalvik.system.NativeStart.main(Native Method)
EDIT: After editing the key in "intent.putExtra" to SSIDString it still returns null.
Debug:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.wdt, PID: 31443
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.wdt/com.example.wdt.MultipleWifi}: java.lang.NullPointerException: storage == null
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2200)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2250)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5105)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException: storage == null
at java.util.Arrays$ArrayList.<init>(Arrays.java:38)
at java.util.Arrays.asList(Arrays.java:155)
at com.example.wdt.MultipleWifi.onCreate(MultipleWifi.java:23)
at android.app.Activity.performCreate(Activity.java:5275)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2164)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2250)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5105)
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:792)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
at dalvik.system.NativeStart.main(Native Method)
You are using wrong key
Intent intent = new Intent(this, MultipleWifi.class);
intent.putExtra("SSIDList", SSIDString);
there is key that you are passing
startActivityForResult(intent, 1);
//change key you are using wrong key here
final String[] StringSSID = intent.getStringArrayExtra("SSIDList");
First take the user permisison!
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED){
requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
PERMISSIONS_REQUEST_CODE_ACCESS_COARSE_LOCATION);
//After this point you wait for callback in onRequestPermissionsResult(int, String[], int[]) overriden method
}else{
getScanningResults();
//do something, permission was previously granted; or legacy device
}
I'm trying to start a third party app(here is Launcher) by using this code:
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
ResolveInfo resolveInfo = getPackageManager().resolveActivity(intent, PackageManager.MATCH_DEFAULT_ONLY);
String currentHomePackage = resolveInfo.activityInfo.packageName;
openApp(getApplicationContext(),currentHomePackage);
openApp:
public static boolean openApp(Context context, String packageName) {
PackageManager manager = context.getPackageManager();
try {
Intent i = manager.getLaunchIntentForPackage(packageName);
if (i == null) {
return false;
//throw new PackageManager.NameNotFoundException();
}
i.addCategory(Intent.CATEGORY_LAUNCHER);
context.startActivity(i);
return true;
} catch (Exception e) {
return false;
}
}
but I get a NullPointerException! This code gets my launcher package name correctly, but I can't open it! Help me please and don't get me negative points!
logcat:
07-30 18:59:47.206 16079-16079/ir.whiteapp.keepme E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at ir.whiteapp.keepme.AlertBox.openApp(AlertBox.java:80)
at ir.whiteapp.keepme.AlertBox$1.onClick(AlertBox.java:52)
at android.view.View.performClick(View.java:4204)
at android.view.View$PerformClick.run(View.java:17355)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
There is no requirement that getLaunchIntentForPackage() return anything. Quoting the documentation:
Returns: A fully-qualified Intent that can be used to launch the main activity in the package. Returns null if the package does not contain such an activity, or if packageName is not recognized.
In particular, a home screen implementation does not need a launch Intent (ACTION_MAIN/CATEGORY_LAUNCHER), as normally it is not launched by other home screen implementations.
My app work strange on diffrent phones - once everything is fine and other time it crash when i try to make photo and save it in my phone's memory. Photo shows up in folder in memory, but when we should come back to application it is shut down:
06-14 23:58:37.448 12344-12344/com.apps.madzia.photo_application E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.apps.madzia.photo_application, PID: 12344
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.apps.madzia.photo_application/com.apps.madzia.photo_application.activity.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2412)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2470)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4053)
at android.app.ActivityThread.access$1000(ActivityThread.java:174)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1313)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5593)
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:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.widget.ArrayAdapter.getCount(ArrayAdapter.java:330)
at android.widget.GridView.setAdapter(GridView.java:187)
at com.apps.madzia.photo_application.fragments.FragmentGallery.onCreateView(FragmentGallery.java:42)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1108)
at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1917)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:544)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1177)
at android.app.Activity.performStart(Activity.java:5468)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2385)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2470)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4053)
at android.app.ActivityThread.access$1000(ActivityThread.java:174)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1313)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5593)
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:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
The code of my function to make photos:
public void make_photo() {
Calendar c;
c = Calendar.getInstance();
imageName = "fotka_" + c.get(Calendar.YEAR) + "_" + c.get(Calendar.MONTH) + "_" + c.get(Calendar.DAY_OF_MONTH)
+ "_" + c.get(Calendar.HOUR_OF_DAY) + "_" + c.get(Calendar.MINUTE) + "_" + c.get(Calendar.SECOND);
File katalog = new File(IMAGE_FILE_PATH);
File photo = new File(IMAGE_FILE_PATH+imageName + ".jpg");
if( Environment.getExternalStorageState() == Environment.MEDIA_UNKNOWN || Environment.getExternalStorageState() == Environment.MEDIA_REMOVED || Environment.getExternalStorageState() == Environment.MEDIA_UNMOUNTED) {
Log.d("ExternalStorage", "cannot find memory SD card");
File file = new File(getFilesDir(), imageName);
IMAGE_FILE_PATH = file.getParent()+"/";
Log.d("IMAGE_FILE_PATH", IMAGE_FILE_PATH);
}else {
}
Log.d("photo", photo.getPath());
if (!katalog.exists()) {
katalog.mkdirs();
}
try {
// fotka = File.createNewFile(imageName, ".jpg", katalog);
photo.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
Intent zdjecie = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
zdjecie.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photo));
startActivityForResult(zdjecie, 1);
}
Caused by: java.lang.NullPointerException
at android.widget.ArrayAdapter.getCount(ArrayAdapter.java:330)
at android.widget.GridView.setAdapter(GridView.java:187)
at com.apps.madzia.photo_application.fragments.FragmentGallery.onCreateView(FragmentGallery.java:42)
This means that in your FragmentGallery in onCreateView method on line 42 u are setting null ArrayAdapter
I have an error on 264 and 163 of two file but in editor it's look fine
line 264 :
if (!mContext.getPackageManager().queryIntentServices(serviceIntent, 0).isEmpty()) {
line 163 :
mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
I can't find why my activity unable to start
Logcat:
1266-1266/com.exercise.AndroidHTML E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.exercise.AndroidHTML/com.company.clipboard.AndroidHTMLActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.company.clipboard.util.IabHelper.startSetup(IabHelper.java:264)
at com.company.clipboard.AndroidHTMLActivity.onCreate(AndroidHTMLActivity.java:163)
at android.app.Activity.performCreate(Activity.java:5008)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at android.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at android.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
This is the whole block of payment that contain line 163:
//=====================================================
String base64EncodedPublicKey = "MIHNMA0GCSqGSIb3DQEBAQUAA4G7ADCBtwKBrwDtUWVdLt6clZldCQGZxcyyWeeBp8vF/6qm7qCKuQPdXg6HB71hVu8lmcEO0VcyS2xpzXt03iW7LhKXRtDsxi5H9wHLESfY9SQUc0ugPD+n5nE+I6zCiB/RB2WscvZFa3JCiYRbmsvez+DwaQSHfq6CNUawl0fbz4NfJntZHKYHanm6PtjquO9JSj+Pa9PV38C3o5Y3ALCvPMCAwEAAQ==";
mHelper = new IabHelper(this, base64EncodedPublicKey);
mGotInventoryListener = new IabHelper.QueryInventoryFinishedListener() {
public void onQueryInventoryFinished(IabResult result, Inventory inventory) {
Log.d(TAG, "Query inventory finished.");
if (result.isFailure()) {
Log.d(TAG, "Failed to query inventory: " + result);
return;
}
else {
Log.d(TAG, "Query inventory was successful.");
// does the user have the premium upgrade?
mIsPremium = inventory.hasPurchase(SKU_PREMIUM);
if (mIsPremium){
MasrafSeke(inventory.getPurchase(SKU_PREMIUM));
}
// update UI accordingly
Log.d(TAG, "User is " + (mIsPremium ? "PREMIUM" : "NOT PREMIUM"));
}
Log.d(TAG, "Initial inventory query finished; enabling main UI.");
}
};
mPurchaseFinishedListener = new IabHelper.OnIabPurchaseFinishedListener() {
public void onIabPurchaseFinished(IabResult result, Purchase purchase) {
if (result.isFailure()) {
Log.d(TAG, "Error purchasing: " + result);
return;
}
else if (purchase.getSku().equals(SKU_PREMIUM)) {
// give user access to premium content and update the UI
Toast.makeText(AndroidHTMLActivity.this,"خرید موفق",Toast.LENGTH_SHORT).show();
MasrafSeke(purchase);
}
}
};
Log.d(TAG, "Starting setup.");
mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
public void onIabSetupFinished(IabResult result) {
Log.d(TAG, "Setup finished.");
if (!result.isSuccess()) {
// Oh noes, there was a problem.
Log.d(TAG, "Problem setting up In-app Billing: " + result);
}
// Hooray, IAB is fully set up!
mHelper.queryInventoryAsync(mGotInventoryListener);
}
});
Seems an issue of IabHelper. The method queryIntentServices returns a null, instead an empty list.
Try to update the code from this:
Intent serviceIntent = new Intent("com.android.vending.billing.InAppBillingService.BIND");
if (!mContext.getPackageManager().queryIntentServices(serviceIntent, 0).isEmpty()) {
// service available to handle that Intent
mContext.bindService(serviceIntent, mServiceConn, Context.BIND_AUTO_CREATE);
}
else {
// no service available to handle that Intent
if (listener != null) {
listener.onIabSetupFinished(
new IabResult(BILLING_RESPONSE_RESULT_BILLING_UNAVAILABLE,
"Billing service unavailable on device."));
}
}
to this:
Intent serviceIntent = new Intent("com.android.vending.billing.InAppBillingService.BIND");
List<ResolveInfo> intentServices = mContext.getPackageManager().queryIntentServices(serviceIntent, 0);
if (intentServices != null && intentServices.isEmpty() == false) {
// service available to handle that Intent
mContext.bindService(serviceIntent, mServiceConn, Context.BIND_AUTO_CREATE);
}
else {
// no service available to handle that Intent
if (listener != null) {
listener.onIabSetupFinished(
new IabResult(BILLING_RESPONSE_RESULT_BILLING_UNAVAILABLE,
"Billing service unavailable on device."));
}
}