I have two activities in my project. There is a button in the main activity when I click it, it takes me to second activity. When I press back button there it's not coming to main activity. It checks for internet first and then when I click button It takes me to second activity.
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
try {
this.getSupportActionBar().hide();
}catch (Exception e){
}
if (isNetworkConnected(this)) {
Button button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent activity2Intent = new Intent(getApplicationContext(), playlive.class);
startActivity(activity2Intent);
}
});
} else {
buildDialog(MainActivity.this).show();
}
}
public static boolean isNetworkConnected(Context context) {
boolean result = false;
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (cm != null) {
NetworkCapabilities capabilities = cm.getNetworkCapabilities(cm.getActiveNetwork());
if (capabilities != null) {
if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
result = true;
} else if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
result = true;
}
}
}
} else {
if (cm != null) {
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
if (activeNetwork != null) {
// connected to the internet
if (activeNetwork.getType() == ConnectivityManager.TYPE_WIFI) {
result = true;
} else if (activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE) {
result = true;
}
}
}
}
return result;
}
This is the error code
Process: com.example.mythrimedia, PID: 3343
java.lang.RuntimeException: Unable to stop activity {com.example.mythrimedia/com.example.mythrimedia.playlive}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.exoplayer2.SimpleExoPlayer.release()' on a null object reference
at android.app.ActivityThread.callActivityOnStop(ActivityThread.java:4624)
at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:4594)
at android.app.ActivityThread.handleStopActivity(ActivityThread.java:4669)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:233)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.exoplayer2.SimpleExoPlayer.release()' on a null object reference
at com.example.mythrimedia.playlive.onStop(playlive.java:76)
at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1466)
at android.app.Activity.performStop(Activity.java:8018)
at android.app.ActivityThread.callActivityOnStop(ActivityThread.java:4616)
at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:4594)
at android.app.ActivityThread.handleStopActivity(ActivityThread.java:4669)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:233)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
second activity
public class playlive extends AppCompatActivity {
private SimpleExoPlayer player;
private PlayerView playerView;
private Uri uri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_playlive);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON, WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
try {
this.getSupportActionBar().hide();
} catch (Exception e) {
}
if (isNetworkConnected(this)) {
play();
} else {
buildDialog(playlive.this).show();
}
}
private void play() {
SimpleExoPlayer player = ExoPlayerFactory.newSimpleInstance(this);
playerView = findViewById(R.id.player_view);
playerView.setPlayer(player);
uri = Uri.parse("http://localhost:1935/live/mystream/index.m3u8");
DataSource.Factory dataSourceFactory =
new DefaultHttpDataSourceFactory(Util.getUserAgent(this, "app-name"));
// Create a HLS media source pointing to a playlist uri.
HlsMediaSource hlsMediaSource =
new HlsMediaSource.Factory(dataSourceFactory).createMediaSource(uri);
player.prepare(hlsMediaSource);
player.setPlayWhenReady(true);
}
public void onStop(){
super.onStop();
player.release();
}
public void onDestroy(){
super.onDestroy();
player.release();
}
public static boolean isNetworkConnected(Context context) {
boolean result = false;
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (cm != null) {
NetworkCapabilities capabilities = cm.getNetworkCapabilities(cm.getActiveNetwork());
if (capabilities != null) {
if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
result = true;
} else if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
result = true;
}
}
}
} else {
if (cm != null) {
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
if (activeNetwork != null) {
// connected to the internet
if (activeNetwork.getType() == ConnectivityManager.TYPE_WIFI) {
result = true;
} else if (activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE) {
result = true;
}
}
}
}
return result;
}
public AlertDialog.Builder buildDialog(Context c) {
AlertDialog.Builder builder = new AlertDialog.Builder(c);
builder.setTitle("No Internet Connection");
builder.setMessage("You need to have Mobile Data or WiFi to Play this. Press ok to Exit");
builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
return builder;
}
}
