I'm implementing to show dialog box when Internet is offline, when i run my app i got "FATAL Exception main" and ClassCastException when when i click on button and application is crash . Can someone tell me what i am doing wrong ? Thanks to you in Advanced.
here is code how i check is internet enabled or not:
public class AndroidDetectInternetConnectionActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btnStatus = (Button) findViewById(R.id.btn_check);
btnStatus.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (!isOnline())
{
showNoConnectionDialog(this);
}
}
});
}
public static void showNoConnectionDialog(OnClickListener onClickListener)
{
final Context ctx = (Context) onClickListener;
AlertDialog.Builder builder = new AlertDialog.Builder(ctx);
builder.setCancelable(true);
builder.setMessage(R.string.no_connection);
builder.setTitle(R.string.no_connection_title);
builder.setPositiveButton(R.string.settings_button_text, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which)
{
ctx.startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS));
}
});
builder.setNegativeButton(R.string.cancel_button_text, new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
return;
}
});
builder.setOnCancelListener(new DialogInterface.OnCancelListener()
{
public void onCancel(DialogInterface dialog) {
return;
}
});
builder.show();
}
public boolean isOnline()
{
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting())
{
return true;
}
return false;
}
}
// This is my Log Cat stack trace
11-15 11:57:19.115: D/AndroidRuntime(453): Shutting down VM
11-15 11:57:19.115: W/dalvikvm(453): threadid=1: thread exiting with uncaught exception (group=0x40015560)
11-15 11:57:19.122: E/AndroidRuntime(453): FATAL EXCEPTION: main
11-15 11:57:19.122: E/AndroidRuntime(453): java.lang.ClassCastException: com.example.detectinternetconnection.AndroidDetectInternetConnectionActivity$1
11-15 11:57:19.122: E/AndroidRuntime(453): at com.example.detectinternetconnection.AndroidDetectInternetConnectionActivity.showNoConnectionDialog(AndroidDetectInternetConnectionActivity.java:99)
11-15 11:57:19.122: E/AndroidRuntime(453): at com.example.detectinternetconnection.AndroidDetectInternetConnectionActivity$1.onClick(AndroidDetectInternetConnectionActivity.java:64)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.view.View.performClick(View.java:2485)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.view.View$PerformClick.run(View.java:9080)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.os.Handler.handleCallback(Handler.java:587)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.os.Handler.dispatchMessage(Handler.java:92)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.os.Looper.loop(Looper.java:123)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.app.ActivityThread.main(ActivityThread.java:3683)
11-15 11:57:19.122: E/AndroidRuntime(453): at java.lang.reflect.Method.invokeNative(Native Method)
11-15 11:57:19.122: E/AndroidRuntime(453): at java.lang.reflect.Method.invoke(Method.java:507)
11-15 11:57:19.122: E/AndroidRuntime(453): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
11-15 11:57:19.122: E/AndroidRuntime(453): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
11-15 11:57:19.122: E/AndroidRuntime(453): at dalvik.system.NativeStart.main(Native Method)
11-15 11:57:24.892: I/Process(453): Sending signal. PID: 453 SIG: 9
change this line
final Context ctx = (Context) onClickListener;
to below one
final Context ctx = AndroidDetectInternetConnectionActivity.this;
basically you are trying to conver onClickListener to Contex which is incorrect and can not be casted.
Either you directly use ActivityName.this wherever you need context instance, or define static Context ctx as a class variable and intialize it in onCreate()by just adding this line ctx =this also remember to intialize it before using it.
Enjoy
There are two ways to solve this problem.
1) showNoConnectionDialog(this); and later on:
public static void showNoConnectionDialog(Context ctx) ...
2) showNoConnectionDialog(); and later on: public void showNoConnectionDialog() { Context ctx = AndroidDetectInternetConnectionActivity.this
You basic problem is generated by the line:
final Context ctx = (Context) onClickListener;
This is simply not a context so trying to force it to be one doesn't work.
I believe that you wanted to do was pass a context (or activity) to this function (as opposed to the local unnamed OnClickListener class that you are now passing)
The easiest solution would be to simple not pass anything to the constructor and use AndroidDetectInternetConnectionActivity.this to access your valid context.
Related
I am quite new to android development and I am facing a NullPointerException when I am trying to call an AsyncTask which is an inner class in another class.
I believe it is the way I am instantiating it but this is what I have:
// This onClick is in my adapter class - which is a separate Java File and class
#Override
public void onClick(View v) {
UploadRes uploadRes = new UploadRes();
UploadRes.UploadResConfirm uploadResConfirm = uploadRes.new UploadResConfirm(v.getContext());
uploadResConfirm.execute(fileName, filePath);
}
public class UploadResConfirm extends AsyncTask<String, String, String> {
Dialog dialog;
Context context;
public UploadResConfirm(Context context){
this.context = context;
}
#Override
protected void onPreExecute(){
dialog = new Dialog(UploadRes.this);
dialog.setTitle("Currently uploading");
dialog.show();
}
I believe it has got something to do with the dialog box itself being instantiated in the AsyncTask class.
The error stack trace on Logcat - its the Dialog, I think its in the wrong place...
java.lang.NullPointerException
at codeman.androapp.UploadRes$UploadResConfirm.onPreExecute(UploadRes.java:246)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
at android.os.AsyncTask.execute(AsyncTask.java:534)
at android.view.View.performClick(View.java:4240)
at android.view.View$PerformClick.run(View.java:17721)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Some help if any would be much obliged.
Instead of dialog = new Dialog(UploadRes.this);
Try
dialog = new Dialog(context);
your are passing a wrong context to create dialog.
I am beginner and I had a test. I did all tasks, but I have a problem -
public class HttpTask extends AsyncTask<Integer, String, String> {####
ProgressDialog dialog;
Context context;
public HttpTask(Activity activity) {
//init progress dialog
dialog = new ProgressDialog(context);****
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
}
protected void onPreExecute() {
// show progress dialog
dialog.setMessage("Loading...");
dialog.setCancelable(false);
}
protected String doInBackground(Integer... params) {
//freeze system to 5 seconds
try {
int seconds = params[0]*5;####
TimeUnit.SECONDS.sleep(seconds);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(final String success) {
// if there is progress dialog hide it
dialog.dismiss();
}
}
It crashes, when I try to compile it (I showed where are problems with * sign):
08-03 10:43:10.873 29441-29441/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:142)
at android.app.AlertDialog.<init>(AlertDialog.java:98)
at android.app.ProgressDialog.<init>(ProgressDialog.java:77)
at net.joerichard.androidtest.main.f.HttpTask.<init>(HttpTask.java:26)
at net.joerichard.androidtest.main.f.F_Networking_Activity$1.onClick(F_Networking_Activity.java:27)
at android.view.View.performClick(View.java:4107)
at android.view.View$PerformClick.run(View.java:17166)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5559)
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:1074)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:841)
at dalvik.system.NativeStart.main(Native Method)
08-03 10:43:10.913 754-877/? E/EmbeddedLogger﹕ App crashed! Process: net.joerichard.androidtest
08-03 10:43:10.913 754-877/? E/EmbeddedLogger﹕ App crashed! Package: net.joerichard.androidtest v1 (1.0)
08-03 10:43:10.913 754-877/? E/EmbeddedLogger﹕ Application Label: AndroidTest
This is class of main activity.
public class F_Networking_Activity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_f__networking_);
// bDownload: start HttpTask
Button bDownload = (Button) findViewById(R.id.bDownload);
bDownload.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
HttpTask task = new HttpTask(F_Networking_Activity.this);****
task.execute();
}
});
}
Thank you for your answers. Now I have another problem (I showed with # sign of second problems)
08-03 11:28:18.292 754-877/? E/EmbeddedLogger﹕ App crashed! Process: net.joerichard.androidtest'
08-03 11:28:18.292 754-877/? E/EmbeddedLogger﹕ App crashed! Package: net.joerichard.androidtest v1 (1.0)
08-03 11:28:18.292 754-877/? E/EmbeddedLogger﹕ Application Label: AndroidTest
08-03 11:28:18.292 30544-30726/? E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at net.joerichard.androidtest.main.f.HttpTask.doInBackground(HttpTask.java:40)
at net.joerichard.androidtest.main.f.HttpTask.doInBackground(HttpTask.java:20)
at android.os.AsyncTask$2.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Actually, your context is null because you didn't initialize it.
Add one extra line inside your HttpTask:
public HttpTask(Activity activity) {
this.context = activity;
dialog = new ProgressDialog(context);
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
}
and change Context to Activity like this:
Activity context;
Now call this context anywhere in your class.
Yes you must get NullPointer. Because your context is null.
Change this like
public HttpTask(Context _context) {
context = _context;
//init progress dialog
dialog = new ProgressDialog(context);****
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
}
I have a TO DO List, and when I check the checkbox in one Activity I want the CheckBox and the text that is next to the Checkbox to go to another Activity. this is my Adapter:
public class MyItemAdapter extends ArrayAdapter<String> {
private final Context context;
private final String[] values;
public MyItemAdapter(Context context, String[] values) {
super(context, R.layout.item_list, values);
this.context = context;
this.values = values;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.item_list, parent, false);
CheckBox textView = (CheckBox) rowView.findViewById(R.id.checkBox1);
textView.setText(values[position]);
return rowView;
}
public static SparseBooleanArray getCheckedItemPositions() {
// TODO Auto-generated method stub
return null;
}
public static void remove(Object pos) {
// TODO Auto-generated method stub
}
public void changeData(String[] items) {
// TODO Auto-generated method stub
}
public static void setAdapter(MyItemAdapter mAdapter) {
// TODO Auto-generated method stub
}
This is my First Activity code:
final CheckBox check = (CheckBox) findViewById(R.id.checkBox1);
check.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, FinishedItems.class);
intent.putExtra("check", items);
Bundle extras = new Bundle();
extras.putString("status", "Data Recived");
intent.putExtras(extras);
startActivity(intent);
}
});
}
This is my Second Activity code:
Intent intent = getIntent();
String check = intent.getStringExtra("check");
((CheckBox)findViewById(R.id.checkBox1)).setText(check);
Bundle bundle = intent.getExtras();
String status = bundle.getString("status");
Toast toast = Toast.makeText(this, status, Toast.LENGTH_LONG);
toast.show();
And Finaly this is my Log cat:
02-18 10:33:24.779: D/AndroidRuntime(1575): Shutting down VM
02-18 10:33:24.779: W/dalvikvm(1575): threadid=1: thread exiting with uncaught exception (group=0x40015560)
02-18 10:33:24.789: E/AndroidRuntime(1575): FATAL EXCEPTION: main
02-18 10:33:24.789: E/AndroidRuntime(1575): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.Stanton.quicktodolist/com.Stanton.quicktodolist.MainActivity}: java.lang.NullPointerException
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.os.Handler.dispatchMessage(Handler.java:99)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.os.Looper.loop(Looper.java:130)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-18 10:33:24.789: E/AndroidRuntime(1575): at java.lang.reflect.Method.invokeNative(Native Method)
02-18 10:33:24.789: E/AndroidRuntime(1575): at java.lang.reflect.Method.invoke(Method.java:507)
02-18 10:33:24.789: E/AndroidRuntime(1575): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-18 10:33:24.789: E/AndroidRuntime(1575): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-18 10:33:24.789: E/AndroidRuntime(1575): at dalvik.system.NativeStart.main(Native Method)
02-18 10:33:24.789: E/AndroidRuntime(1575): Caused by: java.lang.NullPointerException
02-18 10:33:24.789: E/AndroidRuntime(1575): at com.Stanton.quicktodolist.MainActivity.onCreate(MainActivity.java:70)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-18 10:33:24.789: E/AndroidRuntime(1575): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
02-18 10:33:24.789: E/AndroidRuntime(1575): ... 11 more
Please Help me
This line of your stacktrace
02-18 10:33:24.789: E/AndroidRuntime(1575): at com.Stanton.quicktodolist.MainActivity.onCreate(MainActivity.java:70)
points you to the error. Line 70 in the MainActivity causes a null pointer. It is often helpful to study and understand stacktraces. If you cannot figure it out yourself, show us the onCreate method of the MainActivity.
I believe that you replace the intent extra by the bundle extra just try this code and let me know pelase
final CheckBox check = (CheckBox) findViewById(R.id.checkBox1);
check.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, FinishedItems.class);
intent.putExtra("check", items);
//Bundle extras = new Bundle();
// extras.putString("status", "Data Recived");
intent.putExtras("status", "Data Recived");
startActivity(intent);
}
});
}
And the int the second activity
Intent intent = getIntent();
String check = intent.getStringExtra("check");
((CheckBox)findViewById(R.id.checkBox1)).setText(check);
// Bundle bundle = intent.getExtras();
String status = intent.getStringExtra("status");
Toast toast = Toast.makeText(this, status, Toast.LENGTH_LONG);
toast.show();
I have this code for show the MediaController, but it give me a fatal error when I'm calling to Show() method.
The MediaPlayer itself working on Service and get Intent from the MediaPlayerControl interface.
My code:
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mediaController = new MediaController(this, false);
mediaController.setMediaPlayer(mediaPlayerControl);
mediaController.setAnchorView(findViewById(R.id.mediaController));
mediaController.setEnabled(true);
mediaController.show(0);
}
//implements MediaPlayerControl interface
private MediaPlayerControl mediaPlayerControl = new MediaPlayerControl()
{
//Override the methods to send Intent to the MediaPlayer Service
....
....
};
my logcat:
07-27 11:03:07.365: E/AndroidRuntime(328): FATAL EXCEPTION: main
07-27 11:03:07.365: E/AndroidRuntime(328): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.radius100fm/com.example.radius100fm.MainActivity}: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.os.Handler.dispatchMessage(Handler.java:99)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.os.Looper.loop(Looper.java:123)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.main(ActivityThread.java:3683)
07-27 11:03:07.365: E/AndroidRuntime(328): at java.lang.reflect.Method.invokeNative(Native Method)
07-27 11:03:07.365: E/AndroidRuntime(328): at java.lang.reflect.Method.invoke(Method.java:507)
07-27 11:03:07.365: E/AndroidRuntime(328): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
07-27 11:03:07.365: E/AndroidRuntime(328): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
07-27 11:03:07.365: E/AndroidRuntime(328): at dalvik.system.NativeStart.main(Native Method)
07-27 11:03:07.365: E/AndroidRuntime(328): Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.ViewRoot.setView(ViewRoot.java:527)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.Window$LocalWindowManager.addView(Window.java:424)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.widget.MediaController.show(MediaController.java:304)
07-27 11:03:07.365: E/AndroidRuntime(328): at com.example.radius100fm.MainActivity.onCreate(MainActivity.java:100)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
07-27 11:03:07.365: E/AndroidRuntime(328): ... 11 more
What is the problem with my code?
Use this method.
#Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if(mediaController != null)
mediaController.show(0);
}
I got the same problem and after several hours got the solution. I did the following:
Summary:
The Activity class implements the interfaces: MediaPlayer.OnPreparedListener and MediaController.MediaPlayerControl
OnCreate. setContentView.
onStart. Create MediaPlayer and MediaController, start the listener with setOnPreparedListener and call prepare() method of MediaPlayer.
Implement method onPrepared. Link the mediaController with the mediaPlayer, start mediaPlayer and here is where the method show() is called using a handler, only when we know that mediaPlayer is ready.
My code:
public class MainActivity extends Activity implements MediaPlayer.OnPreparedListener, MediaController.MediaPlayerControl {
private static final String TAG = "AudioPlayer";
private MediaPlayer mediaPlayer;
private MediaController mediaController;
private Handler handler = new Handler();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
protected void onStart() {
Log.d(TAG, "Play - onStart");
super.onStart();
mediaPlayer = new MediaPlayer();
mediaController = new MediaController(this);
mediaPlayer.setOnPreparedListener(this);
try {
AssetFileDescriptor afd = getApplicationContext().getResources().openRawResourceFd(R.raw.audio_example);
mediaPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getDeclaredLength());
mediaPlayer.prepare();
afd.close();
} catch (IOException e) {
Log.e(TAG, "Error opening audio: " + e.getCause());
}
}
// override this method because of the OnPreparedListener interface
#Override
public void onPrepared(MediaPlayer mediaPlayer) {
Log.d(TAG, "Play - onPrepared");
mediaController.setMediaPlayer(this);
mediaController.setAnchorView(findViewById(R.id.mediaController1));
mediaPlayer.start();
handler.post(new Runnable() {
#Override
public void run() {
mediaController.setEnabled(true);
mediaController.show(0);
}
});
}
// override these methods because of the MediaController.MediaPlayerControl interface
#Override
public boolean canPause() {
return true;
}
#Override
public boolean canSeekBackward() {
return true;
}
#Override
public boolean canSeekForward() {
return true;
}
#Override
public int getAudioSessionId() {
// TODO Auto-generated method stub
return 0;
}
#Override
public int getBufferPercentage() {
// TODO Auto-generated method stub
return 0;
}
#Override
public int getCurrentPosition() {
return mediaPlayer.getCurrentPosition();
}
#Override
public int getDuration() {
return mediaPlayer.getDuration();
}
#Override
public boolean isPlaying() {
return mediaPlayer.isPlaying();
}
#Override
public void pause() {
mediaPlayer.pause();
}
#Override
public void seekTo(int pos) {
mediaPlayer.seekTo(pos);
}
#Override
public void start() {
mediaPlayer.start();
}
// release resources before kill the Activity
#Override
protected void onStop() {
Log.d(TAG, "Play - onStop");
super.onStop();
if (mediaPlayer != null) {
mediaController.hide();
mediaPlayer.stop();
mediaPlayer.release();
mediaPlayer = null;
}
} }
Ok, so finely I found the answer.
The problem is in the line:
mediaController.show(0);
Because it called in onCreate() and the app still not activated.
Simple tried, add bottom that callingmediaController.show(0); when it clicked, and the app work perfect.
So now I have to call this line after the app get activate.
I'm tried onStart() and onResume() and it not working. The same error logCat.
How can I fix that??
I needed to show the MediaController to a already running MediaPlayer, so I couldn't set the OnPreparedListener like e_v_e said.
With the answer to this question: Can't fix MediaController.show() exception I discovered that the show method is been called before all the activity lifecycle methods were called. The solution proposed there(setting a delay to show) works, but to avoid the delay, you can place the show inside the onAttachedToWindow method, that is called after all the activity lifecycle methods.
Just put the mediaPlayer.prepare() and mediaPlayer.start() in a thread like handler or AsyncTask and done.
If you are using kotlin and anko lib, you can put it in doAsync {}.
I have been trying to program a twitter client for Android (using twitter4j). So far the idea is to have a simple GUI, and if there is not a file with the OAuth token in the SD Card, connect to the Twitter API using AsyncTask, get the URL for the authorization and open the default browser. However, the browser never runs. Depending on the different modifications I have made trying to fix this, either the Activity starts normally but the browser never starts or the Activity crashes. I have come to a point of a a little of frustation and confussion. Can someone point out what's wrong with my code?
public class StatusActivity extends Activity {
private static final String TAG = "StatusActivity";
EditText editText;
Button updateButton;
File oauthfile = null;
public Context context = getApplicationContext();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_status);
Log.d(TAG, "started");
// Find views
editText = (EditText) findViewById(R.id.editText); //
updateButton = (Button) findViewById(R.id.buttonUpdate);
oauthfile = new File("sdcard/auth_file.txt");
//Check if the file with the keys exist
if (oauthfile.exists()==false){
Log.d(TAG, "file not created");
Context context = getApplicationContext();
Toast toast = Toast.makeText(context, "file not created.", Toast.LENGTH_SHORT);
toast.show();
new Authorization(context).execute();
}
}
public void openBrowser (View v){
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com"));
startActivity(browserIntent);
Log.d(TAG, "onclick");
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.status, menu);
return true;
}
}
class Authorization extends AsyncTask <String, Integer, String>{
String url = null;
private Context context;
Authorization(Context context) {
this.context = context.getApplicationContext();
}
public void onPreExecute() {
super.onPreExecute();
Toast.makeText(context, "Invoke onPreExecute()", Toast.LENGTH_SHORT).show();
}
#Override
public String doInBackground(String... params) {
ConfigurationBuilder configBuilder = new ConfigurationBuilder();
configBuilder.setDebugEnabled(true)
//I have eliminated the keys from the question :)
.setOAuthConsumerKey("XXXXXXXXXXXXXX")
.setOAuthConsumerSecret("XXXXXXXXXXXXXXX");
Twitter OAuthTwitter = new TwitterFactory(configBuilder.build()).getInstance();
RequestToken requestToken = null;
AccessToken accessToken = null;
do{
try {
requestToken = OAuthTwitter.getOAuthRequestToken();
url = requestToken.getAuthorizationURL();
}
catch (TwitterException ex) {
ex.printStackTrace();
}
}
while (accessToken==null);
return url;
}
protected void onPostExecute(String result) {
super.onPostExecute(result);
Toast.makeText(context, "Opening browser.", Toast.LENGTH_SHORT).show();
Intent browserIntent = new Intent(Intent.ACTION_ALL_APPS, Uri.parse(url));
context.startActivity(browserIntent);
}
}
I know that at least checks if the file for the tokens exists because the toast "file not created" appears, and that the activity is able to run the browser if I press the button. The app has permissions to write in the SD card and use the Internet. Thanks in advance.
Logcat Trace:
03-28 19:02:32.816: E/AndroidRuntime(278): FATAL EXCEPTION: main
03-28 19:02:32.816: E/AndroidRuntime(278): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.versec.pardinus/com.versec.pardinus.StatusActivity}: java.lang.NullPointerException
03-28 19:02:32.816: E/AndroidRuntime(278): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.os.Handler.dispatchMessage(Handler.java:99)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.os.Looper.loop(Looper.java:123)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.app.ActivityThread.main(ActivityThread.java:4627)
03-28 19:02:32.816: E/AndroidRuntime(278): at java.lang.reflect.Method.invokeNative(Native Method)
03-28 19:02:32.816: E/AndroidRuntime(278): at java.lang.reflect.Method.invoke(Method.java:521)
03-28 19:02:32.816: E/AndroidRuntime(278): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-28 19:02:32.816: E/AndroidRuntime(278): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-28 19:02:32.816: E/AndroidRuntime(278): at dalvik.system.NativeStart.main(Native Method)
03-28 19:02:32.816: E/AndroidRuntime(278): Caused by: java.lang.NullPointerException
03-28 19:02:32.816: E/AndroidRuntime(278): at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:100)
03-28 19:02:32.816: E/AndroidRuntime(278): at com.versec.pardinus.StatusActivity.<init>(StatusActivity.java:30)
03-28 19:02:32.816: E/AndroidRuntime(278): at java.lang.Class.newInstanceImpl(Native Method)
03-28 19:02:32.816: E/AndroidRuntime(278): at java.lang.Class.newInstance(Class.java:1429)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
03-28 19:02:32.816: E/AndroidRuntime(278): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
03-28 19:02:32.816: E/AndroidRuntime(278): ... 11 more
This is what is causing your crash.
public Context context = getApplicationContext();
You're not even using it when you need it, so you can just get rid of this line.
Btw, something else I noticed while looking at your code is this:
oauthfile = new File("sdcard/auth_file.txt");
Don't take the "sdcard/" path for granted. Use this instead:
File dir = Environment.getExternalStorageDirectory();
File oauthfile = new File(dir, "auth_file.txt");