Below is the code of loading frameanimation for two different images on the occurrence of different events.First event is while the activity start.Others are the onTouch() where i making use of GestureDetector for the onDown() and onScroll() The problem is that i get NullPointerException while its in the OnScroll().I found that it is not getting the Y coordinates what can be the issue.
package com.example.animationtry;
import android.os.Bundle;
import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.widget.ImageView;
public class MainActivity extends Activity
{
ImageView img,img1;
AnimationDrawable animation;
private GestureDetector gestureDetector;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
img=(ImageView)findViewById(R.id.image);
img.post(new Runnable()
{
public void run()
{
img.setBackgroundResource(R.anim.frameanimation);
AnimationDrawable frameAnimation = (AnimationDrawable) img .getBackground();
frameAnimation.setVisible(false, true);
frameAnimation.start();
}
});
img.setOnTouchListener(new View.OnTouchListener()
{
public boolean onTouch(View v, MotionEvent event)
{
String img="img";
gestureDetector = new GestureDetector(new MyGestureDetector(img));
if (gestureDetector.onTouchEvent(event))
{
return true;
}
return false;
}
});
img1=(ImageView)findViewById(R.id.image1);
img.post(new Runnable()
{
public void run()
{
img1.setBackgroundResource(R.anim.frameanimation);
AnimationDrawable frameAnimation = (AnimationDrawable) img1.getBackground();
frameAnimation.setVisible(false, true);
frameAnimation.start();
}
});
img1.setOnTouchListener(new View.OnTouchListener()
{
public boolean onTouch(View v, MotionEvent event)
{
String img1="img1";
gestureDetector = new GestureDetector(new MyGestureDetector(img1));
if (gestureDetector.onTouchEvent(event))
{
return true;
}
return false;
}
});
}
class MyGestureDetector extends SimpleOnGestureListener
{
private static final int SWIPE_MAX_OFF_PATH = 40;
private static final int SWIPE_THRESHOLD_VELOCITY = 30;
String viewname;
public MyGestureDetector(String view)
{
viewname=view;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,float velocityY)
{
return true;
}
@Override
public boolean onDown(MotionEvent e)
{
Log.i("View Name",viewname);
if(viewname.equalsIgnoreCase("img"))
{
img.setBackgroundResource(R.anim.clickanimation);
animation = (AnimationDrawable)img.getBackground();
animation.setVisible(false, true);
animation.start();
}
else if(viewname.equalsIgnoreCase("img1"))
{
img1.setBackgroundResource(R.anim.clickanimation);
animation = (AnimationDrawable)img1.getBackground();
animation.setVisible(false, true);
animation.start();
}
return true;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,float distanceX, float distanceY)
{
Log.i("y1",Float.toString(e1.getY()));
Log.i("y2",Float.toString(e2.getY()));
Log.i("Drag View Name",viewname);
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH && Math.abs(distanceY) > SWIPE_THRESHOLD_VELOCITY)
{
if(viewname.equalsIgnoreCase("img"))
{
img.setBackgroundResource(R.anim.draganimaton);
animation = (AnimationDrawable)img.getBackground();
animation.setVisible(false, true);
animation.start();
}
else if(viewname.equalsIgnoreCase("img1"))
{
img1.setBackgroundResource(R.anim.draganimaton);
animation = (AnimationDrawable)img1.getBackground();
animation.setVisible(false, true);
animation.start();
}
return true;
}
return true;
}
}
}
and below is the logcat:
01-12 06:12:22.637: E/AndroidRuntime(1062): FATAL EXCEPTION: main
01-12 06:12:22.637: E/AndroidRuntime(1062): java.lang.NullPointerException
01-12 06:12:22.637: E/AndroidRuntime(1062): at com.example.animationtry.MainActivity$MyGestureDetector.onScroll(MainActivity.java:117)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.GestureDetector.onTouchEvent(GestureDetector.java:541)
01-12 06:12:22.637: E/AndroidRuntime(1062): at com.example.animationtry.MainActivity$4.onTouch(MainActivity.java:69)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.View.dispatchTouchEvent(View.java:3881)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
01-12 06:12:22.637: E/AndroidRuntime(1062): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1691)
01-12 06:12:22.637: E/AndroidRuntime(1062): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1125)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.app.Activity.dispatchTouchEvent(Activity.java:2096)
01-12 06:12:22.637: E/AndroidRuntime(1062): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1675)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2194)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.view.ViewRoot.handleMessage(ViewRoot.java:1878)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.os.Handler.dispatchMessage(Handler.java:99)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.os.Looper.loop(Looper.java:123)
01-12 06:12:22.637: E/AndroidRuntime(1062): at android.app.ActivityThread.main(ActivityThread.java:3683)
01-12 06:12:22.637: E/AndroidRuntime(1062): at java.lang.reflect.Method.invokeNative(Native Method)
01-12 06:12:22.637: E/AndroidRuntime(1062): at java.lang.reflect.Method.invoke(Method.java:507)
01-12 06:12:22.637: E/AndroidRuntime(1062): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-12 06:12:22.637: E/AndroidRuntime(1062): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-12 06:12:22.637: E/AndroidRuntime(1062): at dalvik.system.NativeStart.main(Native Method)
