Android实现图片放大缩小

来源：互联网发布：mac无法充电编辑：程序博客网时间：2024/04/30 13:44

package com.min.Test_Gallery;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.graphics.Matrix;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.GestureDetector;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.view.GestureDetector.OnGestureListener;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.Toast;

public class DisplayImage extends Activity implements OnTouchListener, OnGestureListener {
   private static final String TAG = "DisplayImage";
   private static final int FLING_MIN_DISTANCE = 100;
   private static final int FLING_MIN_VELOCITY = 200;


   /* 相关变量声明 */
   private ImageView mImageView;
   private Button mButton01;
   private Button mButton02;
   private FrameLayout layout1;
   private LinearLayout layoutImage;
   private Bitmap bmp;
   private int id=0;
   private int displayWidth;
   private int displayHeight;
   private float scaleWidth=1;
   private float scaleHeight=1;
   private GestureDetector mGestureDetector;

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState)    {
       super.onCreate(savedInstanceState);
       /* 加载display.xml Layout */
       setContentView(R.layout.display);

       /* 取得屏幕分辨率大小 */
       DisplayMetrics dm=new DisplayMetrics();
       getWindowManager().getDefaultDisplay().getMetrics(dm);
       displayWidth=dm.widthPixels;
       displayHeight=dm.heightPixels;

       /* 初始化相关变量 */
       Bundle bundle = this.getIntent().getExtras();
       Integer imageId = bundle.getInt("imageId");
       Log.i(TAG, "onCreate, imageId = " + imageId);

       bmp=BitmapFactory.decodeResource(getResources(), imageId);
       mImageView = (ImageView)findViewById(R.id.myImageView);
       mImageView.setImageBitmap(bmp);
       mImageView.setOnTouchListener(this);
       mImageView.setLongClickable(true);

       layout1 = (FrameLayout)findViewById(R.id.layout1);
       layoutImage = (LinearLayout)findViewById(R.id.layoutImage);
       mButton01 = (Button)findViewById(R.id.myButton1);
       mButton02 = (Button)findViewById(R.id.myButton2);

       /* 缩小按钮onClickListener */
       mButton01.setOnClickListener(new Button.OnClickListener() {
           @Override
           public void onClick(View v) {
               small();
           }
       });

       /* 放大按钮onClickListener */
       mButton02.setOnClickListener(new Button.OnClickListener() {
           @Override
           public void onClick(View v) {
               big();
           }
       });
   }

   // 用户轻触触摸屏，由1个MotionEvent ACTION_DOWN触发
   @Override
   public boolean onDown(MotionEvent e) {
       // TODO Auto-generated method stub
//       Toast.makeText(this, "onDown", Toast.LENGTH_SHORT).show();
       Log.i(TAG, "onDown...");

       return false;
   }

   /* 用户按下触摸屏、快速移动后松开，由1个MotionEvent ACTION_DOWN,
   * 多个ACTION_MOVE, 1个ACTION_UP触发
   * 参数解释：
   * e1：第1个ACTION_DOWN MotionEvent
   * e2：最后一个ACTION_MOVE MotionEvent
   * velocityX：X轴上的移动速度，像素/秒
   * velocityY：Y轴上的移动速度，像素/秒
   * 触发条件：
   * X轴的坐标位移大于FLING_MIN_DISTANCE，且移动速度大于FLING_MIN_VELOCITY个像素/秒
   * @see android.view.GestureDetector$OnGestureListener#onFling(android.view.MotionEvent, android.view.MotionEvent, float, float)
   */
   @Override
   public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
           float velocityY) {
       // TODO Auto-generated method stub
       Log.i(TAG, "onFling...");

       if (e1.getX() - e2.getX() > FLING_MIN_DISTANCE
                 && Math.abs(velocityX) > FLING_MIN_VELOCITY) {
           // Fling left

             Toast.makeText(this, "Fling Left", Toast.LENGTH_SHORT).show();
         } else if (e2.getX() - e1.getX() > FLING_MIN_DISTANCE
                 && Math.abs(velocityX) > FLING_MIN_VELOCITY) {

           // Fling right

             Toast.makeText(this, "Fling Right", Toast.LENGTH_SHORT).show();
         }

       return false;
   }

   // 用户长按触摸屏，由多个MotionEvent ACTION_DOWN触发
   @Override
   public void onLongPress(MotionEvent e) {
       // TODO Auto-generated method stub
       Log.i(TAG, "onLongPress...");

   }

   // 用户按下触摸屏，并拖动，由1个MotionEvent ACTION_DOWN, 多个ACTION_MOVE触发
   @Override
   public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
           float distanceY) {
       // TODO Auto-generated method stub
       Log.i(TAG, "onScroll...");

       return false;
   }

   // 用户轻触触摸屏，尚未松开或拖动，由一个1个MotionEvent ACTION_DOWN触发
   // 注意和onDown()的区别，强调的是没有松开或者拖动的状态
   @Override
   public void onShowPress(MotionEvent e) {
       // TODO Auto-generated method stub
       Log.i(TAG, "onShowPress...");

   }

   // 用户（轻触触摸屏后）松开，由一个1个MotionEvent ACTION_UP触发
   @Override
   public boolean onSingleTapUp(MotionEvent e) {
       // TODO Auto-generated method stub
       Log.i(TAG, "onSingleTapUp...");

       return false;
   }

   @Override
   public boolean onTouch(View v, MotionEvent event) {
       // TODO Auto-generated method stub
       Log.i(TAG, "onTouch...");

       // Set button visible
       mButton01.setVisibility(View.VISIBLE);
       mButton02.setVisibility(View.VISIBLE);

       return mGestureDetector.onTouchEvent(event);
   }

//   @Override
//   public boolean onTouchEvent(MotionEvent event) {
//       // TODO Auto-generated method stub
//       super.onTouchEvent(event);
//
//       Log.i(TAG, "onTouchEvent");
//       // Set button visible
//       mButton01.setVisibility(View.VISIBLE);
//       mButton02.setVisibility(View.VISIBLE);
//
//       return true;
//   }

   @Override
   public boolean onKeyDown(int keyCode, KeyEvent event) {
       // TODO Auto-generated method stub
       super.onKeyDown(keyCode, event);

       Log.i(TAG, "onKeyDown...");
       // Set button visible
       mButton01.setVisibility(View.VISIBLE);
       mButton02.setVisibility(View.VISIBLE);

       return true;
   }

   /* 图片缩小的method */
   private void small()    {
       int bmpWidth=bmp.getWidth();
       int bmpHeight=bmp.getHeight();

       Log.i(TAG, "bmpWidth = " + bmpWidth + ", bmpHeight = " + bmpHeight);

       /* 设置图片缩小的比例 */
       double scale=0.8;
       /* 计算出这次要缩小的比例 */
       scaleWidth=(float) (scaleWidth*scale);
       scaleHeight=(float) (scaleHeight*scale);
       /* 产生reSize后的Bitmap对象 */
       Matrix matrix = new Matrix();
       matrix.postScale(scaleWidth, scaleHeight);
       Bitmap resizeBmp = Bitmap.createBitmap(bmp,0,0,bmpWidth,
               bmpHeight,matrix,true);

       if(id==0)      {
           /* 如果是第一次按，就删除原来默认的ImageView */
           layoutImage.removeView(mImageView);
       } else {
           /* 如果不是第一次按，就删除上次放大缩小所产生的ImageView */
           layoutImage.removeView((ImageView)findViewById(id));
       }

       /* 产生新的ImageView，放入reSize的Bitmap对象，再放入Layout中 */
       id++;
       ImageView imageView = new ImageView(this);
       imageView.setId(id);
       imageView.setImageBitmap(resizeBmp);
       layoutImage.addView(imageView);
       Log.i(TAG, "imageView.getWidth() = " + imageView.getWidth()
               + ", imageView.getHeight() = " + imageView.getHeight());
       setContentView(layout1);
       /* 因为图片放到最大时放大按钮会disable，所以在缩小时把它重设为enable */
       mButton02.setEnabled(true);
       mButton02.setTextColor(Color.MAGENTA);
   }

   /* 图片放大的method */
   private void big() {
       int bmpWidth=bmp.getWidth();
       int bmpHeight=bmp.getHeight();

       Log.i(TAG, "bmpWidth = " + bmpWidth + ", bmpHeight = " + bmpHeight);

       /* 设置图片放大的比例 */
       double scale=1.25;
       /* 计算这次要放大的比例 */
       scaleWidth=(float)(scaleWidth*scale);
       scaleHeight=(float)(scaleHeight*scale);
       /* 产生reSize后的Bitmap对象 */
       Matrix matrix = new Matrix();
       matrix.postScale(scaleWidth, scaleHeight);
       Bitmap resizeBmp = Bitmap.createBitmap(bmp,0,0,bmpWidth,
               bmpHeight,matrix,true);

       if(id==0) {
           /* 如果是第一次按，就删除原来设置的ImageView */
           layoutImage.removeView(mImageView);
       } else {
           /* 如果不是第一次按，就删除上次放大缩小所产生的ImageView */
           layoutImage.removeView((ImageView)findViewById(id));
       }

       /* 产生新的ImageView，放入reSize的Bitmap对象，再放入Layout中 */
       id++;
       ImageView imageView = new ImageView(this);
       imageView.setId(id);
       imageView.setImageBitmap(resizeBmp);
       layoutImage.addView(imageView);
       setContentView(layout1);
       /* 如果再放大会超过屏幕大小，就把Button disable */
       if( scaleWidth * scale * bmpWidth > bmpWidth * 3 ||
           scaleHeight * scale * bmpHeight > bmpWidth * 3 ||
           scaleWidth * scale * bmpWidth > displayWidth * 5 ||
           scaleHeight * scale * bmpHeight > displayHeight * 5) {
               mButton02.setEnabled(false);
               mButton02.setTextColor(Color.GRAY);
           } else {
               mButton02.setEnabled(true);
               mButton02.setTextColor(Color.MAGENTA);
           }
       }

}

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/layout1"
    >

    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
       android:layout_weight="19"
       android:scrollbars="vertical"
       android:fadingEdge="vertical">
   <HorizontalScrollView
       android:layout_height="fill_parent"
       android:layout_width="wrap_content">
        <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:orientation="horizontal"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:id="@+id/layoutImage"
            >
            <ImageView
               android:id="@+id/myImageView"
               android:layout_width="fill_parent"
               android:layout_height="wrap_content"
               android:layout_weight="19"
               android:paddingTop="5dip"
               android:paddingBottom="5dip"
               />
       </LinearLayout>
   </HorizontalScrollView >
   </ScrollView>

   <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        >
        <Button
           android:id="@+id/myButton1"
           android:layout_width="45dip"
           android:layout_height="30dip"
           android:layout_alignParentLeft="true"
           android:gravity="left"
           style="@style/my_style_button"
           android:visibility="gone"
           android:text="缩小"
           />
       <Button
           android:id="@+id/myButton2"
           android:layout_width="45dip"
           android:layout_height="30dip"
           android:layout_alignParentRight="true"
           android:gravity="right"
           style="@style/my_style_button"
           android:visibility="gone"
           android:text="放大"
           />
    </RelativeLayout>
</FrameLayout>

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