In this exercise, we will implement our OnTouchListener to handle the following MotionEvent:
ACTION_DOWN: A pressed gesture has started, the motion contains the initial starting location.
ACTION_POINTER_DOWN: A non-primary pointer has gone down.
ACTION_MOVE: A change has happened during a press gesture (between ACTION_DOWN and ACTION_UP).
ACTION_UP: A pressed gesture has finished.
ACTION_POINTER_UP: A non-primary pointer has gone up.
It will be used to implement our pinch zoom in coming exercise.
Download the files.
ACTION_DOWN: A pressed gesture has started, the motion contains the initial starting location.
ACTION_POINTER_DOWN: A non-primary pointer has gone down.
ACTION_MOVE: A change has happened during a press gesture (between ACTION_DOWN and ACTION_UP).
ACTION_UP: A pressed gesture has finished.
ACTION_POINTER_UP: A non-primary pointer has gone up.
It will be used to implement our pinch zoom in coming exercise.
package com.exercise.AndroidTouchPinchZoom;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
import android.widget.TextView;
public class AndroidTouchPinchZoomActivity extends Activity {
TextView myTouchEvent;
ImageView myImageView;
Bitmap bitmap;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myTouchEvent = (TextView)findViewById(R.id.touchevent);
myImageView = (ImageView)findViewById(R.id.imageview);
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
myImageView.setImageBitmap(bitmap);
myImageView.setOnTouchListener(MyOnTouchListener);
}
OnTouchListener MyOnTouchListener
= new OnTouchListener(){
@Override
public boolean onTouch(View view, MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction() & MotionEvent.ACTION_MASK){
case MotionEvent.ACTION_DOWN:
//A pressed gesture has started, the motion contains the initial starting location.
myTouchEvent.setText("ACTION_DOWN");
break;
case MotionEvent.ACTION_POINTER_DOWN:
//A non-primary pointer has gone down.
myTouchEvent.setText("ACTION_POINTER_DOWN");
break;
case MotionEvent.ACTION_MOVE:
//A change has happened during a press gesture (between ACTION_DOWN and ACTION_UP).
myTouchEvent.setText("ACTION_MOVE");
break;
case MotionEvent.ACTION_UP:
//A pressed gesture has finished.
myTouchEvent.setText("ACTION_UP");
break;
case MotionEvent.ACTION_POINTER_UP:
//A non-primary pointer has gone up.
myTouchEvent.setText("ACTION_POINTER_UP");
break;
}
return true;
}
};
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<TextView
android:id="@+id/touchevent"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<ImageView
android:id="@+id/imageview"
android:layout_gravity="center"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:scaleType="center" />
</LinearLayout>
