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Implement GestureDetector/OnGestureListener to detect Fling, and ObjectAnimator for ImageView

In this exercise, I will implement GestureDetector with OnGestureListener for a ImageView of icon. Once the user fling on the icon, it will be moved (animated using ObjectAnimator).

package com.example.androidanimatefling; import android.os.Bundle; import android.animation.ObjectAnimator; import android.app.Activity; import android.util.DisplayMetrics; import android.view.GestureDetector; import android.view.MotionEvent; import android.view.View; import android.view.GestureDetector.OnGestureListener; import android.view.View.OnTouchListener; import android.widget.FrameLayout; import android.widget.ImageView; import android.widget.TextView; public class MainActivity extends Activity { TextView info; ImageView flingObj; FrameLayout mainScreen; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); info = (TextView)findViewById(R.id.info); flingObj = (ImageView)findViewById(R.id.flingobject); mainScreen = (FrameLayout)findViewById(R.id.mainscreen); final GestureDetector myGesture = new GestureDetector(this, new MyOnGestureListener()); flingObj.setOnTouchListener(new OnTouchListener(){ @Override public boolean onTouch(View v, MotionEvent event) { return myGesture.onTouchEvent(event); }}); flingObj.setClickable(true); } class MyOnGestureListener implements OnGestureListener{ int MIN_DIST = 100; @Override public boolean onDown(MotionEvent arg0) { // TODO Auto-generated method stub return false; } @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { float e1X = e1.getX(); float e1Y = e1.getY(); float e2X = e2.getX(); float e2Y = e2.getY(); float distX = e2X - e1X; float distY = e2Y - e1Y; info.setText( "e1X e1Y : " + String.valueOf(e1X) + " : " + String.valueOf(e1Y) + "\n" + "e2X e2Y : " + String.valueOf(e2X) + " : " + String.valueOf(e2Y) + "\n" + "velocityX : " + String.valueOf(velocityX) + "\n" + "velocityY : " + String.valueOf(velocityY)); //Get the Y OFfset DisplayMetrics displayMetrics = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(displayMetrics); int offsetY = displayMetrics.heightPixels - mainScreen.getMeasuredHeight(); int[] location = new int[2]; flingObj.getLocationOnScreen(location); float orgX = location[0]; float orgY = location[1] - offsetY; float stopX = orgX + distX; float stopY = orgY + distY; if (distX > MIN_DIST) { //Fling Right ObjectAnimator flingAnimator = ObjectAnimator.ofFloat(flingObj, "translationX", orgX, stopX); flingAnimator.setDuration(1000); flingAnimator.start(); }else if(distX < - MIN_DIST){ //Fling Left ObjectAnimator flingAnimator = ObjectAnimator.ofFloat(flingObj, "translationX", orgX, stopX); flingAnimator.setDuration(1000); flingAnimator.start(); }else if (distY > MIN_DIST) { //Fling Down ObjectAnimator flingAnimator = ObjectAnimator.ofFloat(flingObj, "translationY", orgY, stopY); flingAnimator.setDuration(1000); flingAnimator.start(); }else if(distY < - MIN_DIST){ //Fling Up ObjectAnimator flingAnimator = ObjectAnimator.ofFloat(flingObj, "translationY", orgY, stopY); flingAnimator.setDuration(1000); flingAnimator.start(); } return true; } @Override public void onLongPress(MotionEvent e) { // TODO Auto-generated method stub } @Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { // TODO Auto-generated method stub return false; } @Override public void onShowPress(MotionEvent e) { // TODO Auto-generated method stub } @Override public boolean onSingleTapUp(MotionEvent e) { // TODO Auto-generated method stub return false; }}; }

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/mainscreen"> <TextView android:id="@+id/info" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <ImageView android:id="@+id/flingobject" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="@dimen/padding_medium" android:src="@drawable/ic_launcher" tools:context=".MainActivity" /> </FrameLayout>

In order to use android.animation.ObjectAnimator, minSdkVersion="11" is needed.