Double-click android to enlarge the image, and then double-click to zoom out the image. [android evolution 9]

 

Today, I wrote a method to handle the onDoubleTap event. Double-click the program to zoom in and out the screen event, double-click the screen image to zoom in, and then double-click the screen image to zoom in to the original effect. See the results!

Source image: double-click the screen to enlarge the effect:

 

 

Paste the code below:

I. Code in MainActivty. java class:

 

Package com.cn. android;

 

Import android. app. Activity;

Import android. OS. Bundle;

Import android. util. Log;

Import android. view. GestureDetector;

Import android. view. KeyEvent;

Import android. view. MotionEvent;

Import android. view. GestureDetector. OnGestureListener;

 

Public class mainActivity extends Activity implements OnGestureListener {

Private ImageShowView mImageShowView = null;

Private GestureDetector gesturetor;

Private double size = 1.0;

@ Override

Public void onCreate (Bundle savedInstanceState ){

Super. onCreate (savedInstanceState );

MImageShowView = new ImageShowView (this );

SetContentView (mImageShowView );

Gesturetor = new GestureDetector (this );

Gestureener. setOnDoubleTapListener (new GestureDetector. OnDoubleTapListener (){

 

@ Override

Public boolean onDoubleTap (MotionEvent e ){

// TODO Auto-generated method stub

// Double-click

If (Scale = 1.0 ){

Scale = Scale + 0.5;

MImageShowView. setScale (Scale );

}

Else if (Scale = 1.5 ){

Scale = Scale-0.5;

MImageShowView. setScale (Scale );

}

Log. v ("daming", "onDoubleTap ");

Return true;

}

 

@ Override

Public boolean onDoubleTapEvent (MotionEvent e ){

// TODO Auto-generated method stub

// Double-click is generated twice

Log. v ("daming", "onDoubleTapEvent ");

Return false;

}

 

@ Override

Public boolean onSingleTapConfirmed (MotionEvent e ){

// One click

Log. v ("daming", "onSingleTapConfirmed ");

Return false;

}

});

}

@ Override

Public boolean onTouchEvent (MotionEvent me ){

Return gesturetries. onTouchEvent (me );

}

 

@ Override

Public boolean onDown (MotionEvent e ){

// TODO Auto-generated method stub

Return false;

}

 

@ Override

Public boolean onFling (MotionEvent e1, MotionEvent e2, float velocityX,

Float velocityY ){

// TODO Auto-generated method stub

Return false;

}

 

@ 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;

}

 

}

 

Ii. Code in ImageShowView. java:

 

Package com.cn. android;

 

Import android. content. Context;

Import android. graphics. Bitmap;

Import android. graphics. Canvas;

Import android. graphics. Matrix;

Import android. graphics. drawable. BitmapDrawable;

Import android. view. KeyEvent;

Import android. view. View;

 

Public class ImageShowView extends View implements Runnable {

 

Bitmap mBitmap = null;

Int mBitmapWidth = 0; // defines the image width.

Int mBitmapHeight = 0; // defines the Image Height.

Private double size = 1.0;

Matrix mMatrix = new Matrix ();

Public ImageShowView (Context context ){

Super (context );

MBitmap = (BitmapDrawable) getResources (). getDrawable (R. drawable. image1). getBitmap ();

MBitmapWidth = mBitmap. getWidth ();

MBitmapHeight = mBitmap. getHeight ();

// Enable the thread

New Thread (this). start ();

}

 

Public void setScale (double scale ){

This. Scale = scale;

}

@ Override

Protected void onDraw (Canvas canvas ){

Super. onDraw (canvas );

MMatrix. reset ();

MMatrix. postScale (float) Scale, (float) Scale); // you can specify a Scale.

Bitmap mBitmap2 = Bitmap. createBitmap (mBitmap, 0, 0, mBitmapWidth, mBitmapHeight, mMatrix, true );

// Draw the rotated image

ImageShowView. drawImage (canvas, mBitmap2, (320-mBitmapWidth)/2,10 );

MBitmap2 = null;

}

 

@ Override

Public void run (){

While (! Thread. currentThread (). isInterrupted ()){

Try {

Thread. sleep (100 );

} Catch (InterruptedException e ){

// TODO Auto-generated catch block

E. printStackTrace ();

}

PostInvalidate ();

}

}

Private static void drawImage (Canvas canvas, Bitmap bitmap, int x, int y ){

// TODO Auto-generated method stub

Canvas. drawBitmap (bitmap, x, y, null );

}

}

 

Note: The above is all my code, and the images in the project will not be uploaded. You can upload an image by yourself. If you need the complete code, you can leave the email address, if you have any questions, please leave a message and I will reply to them! If you have good suggestions, you can come up with them, learn together, and make progress together!

 

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