android 双击图片放大，再双击缩小效果 【安卓进化九】
16lz
2021-01-26
今天写了个onDoubleTap事件的处理方法，双击屏幕事件的放大缩小的程序，双击屏幕图片放大，再双击屏幕图片缩小到原来的效果。请看截图的效果！
原图： 双击屏幕放大后的效果：
现把代码贴出来：
一、MainActivty.java类中的代码：
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 gestureScanner; private double Scale = 1.0; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mImageShowView = new ImageShowView(this); setContentView(mImageShowView); gestureScanner = new GestureDetector(this); gestureScanner.setOnDoubleTapListener(new GestureDetector.OnDoubleTapListener(){ @Override public boolean onDoubleTap(MotionEvent e) { // TODO Auto-generated method stub // 双击时产生一次 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 // 双击时产生两次 Log.v("daming", "onDoubleTapEvent"); return false; } @Override public boolean onSingleTapConfirmed(MotionEvent e) { //短快的点击算一次单击 Log.v("daming", "onSingleTapConfirmed"); return false; } }); } @Override public boolean onTouchEvent(MotionEvent me) { return gestureScanner.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; } } 二、ImageShowView.java中的代码：
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;//定义图片的宽 int mBitmapHeight = 0;//定义图片的高 private double Scale = 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(); //开启线程 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);//设置缩放 Bitmap mBitmap2 = Bitmap.createBitmap(mBitmap,0,0,mBitmapWidth,mBitmapHeight,mMatrix,true); //绘制旋转之后的图像 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); }}
说明：以上就是我的全部代码，项目中的图片就不上传了，大家可以自己传个图片上去就可以了，有需要完整代码的可以留邮箱，大家有任何问题，可以给我留言，我看到就回复！大家有好的意见可以提出来，共同学习，共同进步！
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