I/m having a NullPointerException and I believe the problem is related to setContentView in the onCreate method.
here is the main activity :
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
and this is the code where I add a text to a textView .. this code is written in another view :
public boolean onTouchEvent(MotionEvent event) {
// get pointer index from the event object
int pointerIndex = event.getActionIndex();
// get pointer ID
int pointerId = event.getPointerId(pointerIndex);
// get masked (not specific to a pointer) action
int maskedAction = event.getActionMasked();
switch (maskedAction) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_DOWN: {
// We have a new pointer. Lets add it to the list of pointers
PointF f = new PointF();
f.x = event.getX(pointerIndex);
f.y = event.getY(pointerIndex);
mActivePointers.put(pointerId, f);
break;
}
case MotionEvent.ACTION_MOVE: { // a pointer was moved
for (int size = event.getPointerCount(), i = 0; i < size; i++) {
PointF point = mActivePointers.get(event.getPointerId(i));
if (point != null) {
point.x = event.getX(i);
point.y = event.getY(i);
}
}
break;
}
case MotionEvent.ACTION_UP:
String schema = getLetterSchema();
String letter = getLetter(schema);
if(letter == null) {
System.out.println("***************************");
System.out.println("****ERROR***"+schema+"***");
System.out.println("***************************");
} else {
TextView t=(TextView)findViewById(R.id.textView);
t.setText(letter);
System.out.println("***************************");
System.out.println("*"+letter+"*");
System.out.println("****************"+schema+"****");
}
mActivePointers.clear();
break;
case MotionEvent.ACTION_POINTER_UP:
// DO NOT USE
break;
case MotionEvent.ACTION_CANCEL: {
// DO NOT USE
mActivePointers.clear();
break;
}
}
;
invalidate();
return true;
}
here is the log :
09-09 18:01:47.221: I/(29842): PLATFORM VERSION : JB-MR-2
09-09 18:01:47.246: D/mali_winsys(29842): new_window_surface returns 0x3000
09-09 18:01:47.321: D/OpenGLRenderer(29842): Enabling debug mode 0
09-09 18:01:50.546: E/InputEventReceiver(29842): Exception dispatching input event.
09-09 18:01:50.551: E/MessageQueue-JNI(29842): Exception in MessageQueue callback: handleReceiveCallback
09-09 18:01:50.556: E/MessageQueue-JNI(29842): java.lang.NullPointerException
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at com.example.multitouch.MultitouchView.onTouchEvent(MultitouchView.java:127)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.View.dispatchTouchEvent(View.java:8112)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2252)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1587)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.app.Activity.dispatchTouchEvent(Activity.java:2507)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2200)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.View.dispatchPointerEvent(View.java:8320)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4558)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4430)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3988)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4042)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4011)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4122)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4019)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4179)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3988)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4042)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4011)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4019)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3988)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6333)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6249)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6220)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6185)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6413)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.os.MessageQueue.nativePollOnce(Native Method)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.os.MessageQueue.next(MessageQueue.java:138)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.os.Looper.loop(Looper.java:123)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at android.app.ActivityThread.main(ActivityThread.java:5335)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at java.lang.reflect.Method.invokeNative(Native Method)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at java.lang.reflect.Method.invoke(Method.java:515)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
09-09 18:01:50.556: E/MessageQueue-JNI(29842): at dalvik.system.NativeStart.main(Native Method)
09-09 18:01:50.556: D/AndroidRuntime(29842): Shutting down VM
09-09 18:01:50.556: W/dalvikvm(29842): threadid=1: thread exiting with uncaught exception (group=0x4175fc08)
09-09 18:01:50.571: E/AndroidRuntime(29842): FATAL EXCEPTION: main
09-09 18:01:50.571: E/AndroidRuntime(29842): Process: com.example.multitouch, PID: 29842
09-09 18:01:50.571: E/AndroidRuntime(29842): java.lang.NullPointerException
09-09 18:01:50.571: E/AndroidRuntime(29842): at com.example.multitouch.MultitouchView.onTouchEvent(MultitouchView.java:127)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.View.dispatchTouchEvent(View.java:8112)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2420)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2153)
09-09 18:01:50.571: E/AndroidRuntime(29842): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2252)
09-09 18:01:50.571: E/AndroidRuntime(29842): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1587)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.app.Activity.dispatchTouchEvent(Activity.java:2507)
09-09 18:01:50.571: E/AndroidRuntime(29842): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2200)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.View.dispatchPointerEvent(View.java:8320)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4558)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4430)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3988)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4042)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4011)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4122)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4019)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4179)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3988)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4042)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4011)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4019)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3988)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6333)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6249)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6220)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6185)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6413)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.os.MessageQueue.nativePollOnce(Native Method)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.os.MessageQueue.next(MessageQueue.java:138)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.os.Looper.loop(Looper.java:123)
09-09 18:01:50.571: E/AndroidRuntime(29842): at android.app.ActivityThread.main(ActivityThread.java:5335)
09-09 18:01:50.571: E/AndroidRuntime(29842): at java.lang.reflect.Method.invokeNative(Native Method)
09-09 18:01:50.571: E/AndroidRuntime(29842): at java.lang.reflect.Method.invoke(Method.java:515)
09-09 18:01:50.571: E/AndroidRuntime(29842): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
09-09 18:01:50.571: E/AndroidRuntime(29842): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
09-09 18:01:50.571: E/AndroidRuntime(29842): at dalvik.system.NativeStart.main(Native Method)
09-09 18:01:53.381: I/Process(29842): Sending signal. PID: 29842 SIG: 9
line 127 is this : t.setText(letter);
here is the main activity :
public class MainActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Your assumption is wrong. It has nothing to do with setContentView(), but rather with your findViewById call. You state that the code is from another view, which means your code is within a class which extends View. But View itself also has a findViewById() method. Below the documentation
Look for a child view with the given id. If this view has the given id, return this view.
Parameters:
id The id to search for.
Returns:
The view that has the given id in the hierarchy or null
And I guess your R.id.textView is not a child of your another view.
You want to call findViewById() on your Context, for example by calling getContext().findViewById(R.id.textView). Hope that helps.