Question

this is my activity code

public class HomeActivity extends Activity {

    private String html = "";
    private Handler mHandler;
    private ActionBar actionBar;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        actionBar = (ActionBar) findViewById(R.id.actionbar);
        actionBar.setHomeAction(new IntentAction(this, createIntent(this), R.drawable.ic_title_home_default));
        actionBar.setTitle("someTitle");



        Intent intent = new Intent(this, ComposeActivity.class);

        final Action otherAction = new IntentAction(this, intent, R.drawable.ic_title_share_default);
        actionBar.addAction(otherAction);

        mHandler = new Handler();  
    }

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        if(hasFocus)
            checkPrice.start();
    }

    public static Intent createIntent(Context context) {
        Intent i = new Intent(context, HomeActivity.class);
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        return i;
    }


    private Thread checkPrice = new Thread() {
        public void run() {
            actionBar.setProgressBarVisibility(View.VISIBLE);
            try {       
               //...some code
                mHandler.post(showUpdate);
            } catch (Exception e) {
            }
        }
    };  

    private Runnable showUpdate = new Runnable(){
        public void run(){
            actionBar.setProgressBarVisibility(View.GONE);
            Toast.makeText(HomeActivity.this, "HTML Code: " + html, Toast.LENGTH_SHORT).show();
        }
    };

}

After adding the onWindowFocusChanged method the Intent intent
cannot be started anymore. I get following error:

 12-12 10:50:02.468: W/dalvikvm(540): threadid=3: thread exiting with
 uncaught exception (group=0x4001b188) 12-12 10:50:02.468:
 E/AndroidRuntime(540): Uncaught handler: thread main exiting due to
 uncaught exception 12-12 10:50:02.468: E/AndroidRuntime(540):
 java.lang.IllegalThreadStateException: Thread already started. 12-12
 10:50:02.468: E/AndroidRuntime(540):   at
 java.lang.Thread.start(Thread.java:1322) 12-12 10:50:02.468:
 E/AndroidRuntime(540):     at
 HomeActivity.onWindowFocusChanged(HomeActivity.java:58)
 12-12 10:50:02.468: E/AndroidRuntime(540):     at
 com.android.internal.policy.impl.PhoneWindow$DecorView.onWindowFocusChanged(PhoneWindow.java:1969)
 12-12 10:50:02.468: E/AndroidRuntime(540):     at
 android.view.View.dispatchWindowFocusChanged(View.java:3731) 12-12
 10:50:02.468: E/AndroidRuntime(540):   at
 android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:657)
12-12 10:50:02.468: E/AndroidRuntime(540):  at
 android.view.ViewRoot.handleMessage(ViewRoot.java:1819) 12-12
 10:50:02.468: E/AndroidRuntime(540):   at
 android.os.Handler.dispatchMessage(Handler.java:99) 12-12
 10:50:02.468: E/AndroidRuntime(540):   at
 android.os.Looper.loop(Looper.java:123) 12-12 10:50:02.468:
 E/AndroidRuntime(540):     at
 android.app.ActivityThread.main(ActivityThread.java:4363) 12-12
 10:50:02.468: E/AndroidRuntime(540):   at
 java.lang.reflect.Method.invokeNative(Native Method) 12-12
 10:50:02.468: E/AndroidRuntime(540):   at
 java.lang.reflect.Method.invoke(Method.java:521) 12-12 10:50:02.468:
 E/AndroidRuntime(540):     at
 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
 12-12 10:50:02.468: E/AndroidRuntime(540):     at
 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 12-12
 10:50:02.468: E/AndroidRuntime(540):   at
 dalvik.system.NativeStart.main(Native Method)

Any ideas how to fix this?

Answer 1

Your onWindowFocusChanged calls Thread.start() several times for the same thread which is incorrect. You may want to use a variable like isStarted to guarantee that Thread.start() is called only once. Or start a new thread each time. That depends on your program’s logic.