Android開發_拖動效果，旋轉效果，兩點放大縮小的實現

[java] 

最近在做一個項目，需要用到拖動圖片，旋轉效果，兩點放大縮小。

首先拖動圖片

布局，主要就是一個button做測試

[html]
<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    > 
<TextView   
    android:layout_width="fill_parent"  
    android:layout_height="wrap_content"  
    android:text="@string/hello" 
    /> 
    <Button 
    android:id="@+id/btn" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="@string/bt" 
    />     
</LinearLayout> 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
    <Button
    android:id="@+id/btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/bt"
    />   
</LinearLayout>

[java]
package com.oppo.examples; 
 
import android.app.Activity; 
import android.os.Bundle; 
import android.util.DisplayMetrics; 
import android.util.Log; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.View.OnTouchListener; 
import android.widget.Button; 
import android.widget.Toast; 
 
public class DraftTest extends Activity { 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
 
        DisplayMetrics dm = getResources().getDisplayMetrics(); 
        final int screenWidth = dm.widthPixels; 
        final int screenHeight = dm.heightPixels - 50; 
 
        final Button b=(Button)findViewById(R.id.btn); 
         
        b.setOnTouchListener(new OnTouchListener(){ 
 
            int lastX, lastY; 
 
            @Override 
            public boolean onTouch(View v, MotionEvent event) { 
                // TODO Auto-generated method stub  
                int ea=event.getAction(); 
                Log.i("TAG", "Touch:"+ea); 
 
                //Toast.makeText(DraftTest.this, "位置："+x+","+y, Toast.LENGTH_SHORT).show();  
 
                switch(ea){ 
                case MotionEvent.ACTION_DOWN: 
                    lastX = (int) event.getRawX(); 
                    lastY = (int) event.getRawY(); 
                    break; 
                    /**
                     * layout(l,t,r,b)
                     * l  Left position, relative to parent 
                    t  Top position, relative to parent 
                    r  Right position, relative to parent 
                    b  Bottom position, relative to parent  
                     * */ 
                case MotionEvent.ACTION_MOVE: 
                    int dx =(int)event.getRawX() - lastX; 
                    int dy =(int)event.getRawY() - lastY; 
                 
                    int left = v.getLeft() + dx; 
                    int top = v.getTop() + dy; 
                    int right = v.getRight() + dx; 
                    int bottom = v.getBottom() + dy; 
                     
                    if(left < 0){ 
                        left = 0; 
                        right = left + v.getWidth(); 
                    } 
                     
                    if(right > screenWidth){ 
                        right = screenWidth; 
                        left = right - v.getWidth(); 
                    } 
                     
                    if(top < 0){ 
                        top = 0; 
                        bottom = top + v.getHeight(); 
                    } 
                     
                    if(bottom > screenHeight){ 
                        bottom = screenHeight; 
                        top = bottom - v.getHeight(); 
                    } 
                     
                    v.layout(left, top, right, bottom); 
                     
                    Log.i("", "position：" + left +", " + top + ", " + right + ", " + bottom); 
    
                    lastX = (int) event.getRawX(); 
                    lastY = (int) event.getRawY(); 
                     
                    break; 
                case MotionEvent.ACTION_UP: 
                    break;               
                } 
                return false; 
            }}); 
    } 
} 

package com.oppo.examples;

import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.Toast;

public class DraftTest extends Activity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  DisplayMetrics dm = getResources().getDisplayMetrics();
  final int screenWidth = dm.widthPixels;
  final int screenHeight = dm.heightPixels - 50;

  final Button b=(Button)findViewById(R.id.btn);
  
  b.setOnTouchListener(new OnTouchListener(){

   int lastX, lastY;

   @Override
   public boolean onTouch(View v, MotionEvent event) {
    // TODO Auto-generated method stub
    int ea=event.getAction();
    Log.i("TAG", "Touch:"+ea);

    //Toast.makeText(DraftTest.this, "位置："+x+","+y, Toast.LENGTH_SHORT).show();

    switch(ea){
    case MotionEvent.ACTION_DOWN:
     lastX = (int) event.getRawX();
     lastY = (int) event.getRawY();
     break;
     /**
      * layout(l,t,r,b)
      * l  Left position, relative to parent
                    t  Top position, relative to parent
                    r  Right position, relative to parent
                    b  Bottom position, relative to parent 
      * */
    case MotionEvent.ACTION_MOVE:
     int dx =(int)event.getRawX() - lastX;
     int dy =(int)event.getRawY() - lastY;
    
     int left = v.getLeft() + dx;
     int top = v.getTop() + dy;
     int right = v.getRight() + dx;
     int bottom = v.getBottom() + dy;
     
     if(left < 0){
      left = 0;
      right = left + v.getWidth();
     }
     
     if(right > screenWidth){
      right = screenWidth;
      left = right - v.getWidth();
     }
     
     if(top < 0){
      top = 0;
      bottom = top + v.getHeight();
     }
     
     if(bottom > screenHeight){
      bottom = screenHeight;
      top = bottom - v.getHeight();
     }
     
     v.layout(left, top, right, bottom);
     
     Log.i("", "position：" + left +", " + top + ", " + right + ", " + bottom);
  
     lastX = (int) event.getRawX();
     lastY = (int) event.getRawY();
     
     break;
    case MotionEvent.ACTION_UP:
     break;          
    }
    return false;
   }});
 }
}

代碼主要實現 public boolean onTouch(View v, MotionEvent event)  方法，對MotionEvent 的各種狀態進行定義 與距離的判斷，ACTION_DOWN，ACTION_MOVE，ACTION_UP

android Bitmap圍繞一個點進行旋轉

在項目中需要使用定位功能，也就是一個點圍繞一個圓心進行旋轉，查看了canvas的函數也就只有一個 canvas.drawBitmap(bitmap, matrix, paint)通過使用Matrix來實現旋轉，這裡實現一個demo，功能就是小原點順時針繪制一個原然後逆時針撤銷這個圓，通過Timer來實現。代碼如下:

Surface.java這個是實現繪制圖形的類

[java]
 package com.example.test; 
 
import java.util.Timer; 
import java.util.TimerTask; 
 
import android.annotation.SuppressLint; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Matrix; 
import android.graphics.Paint; 
import android.graphics.PixelFormat; 
import android.graphics.PorterDuff.Mode; 
import android.os.Handler; 
import android.os.Message; 
import android.util.Log; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.SurfaceHolder.Callback; 
 
@SuppressLint("HandlerLeak") 
class Surface extends SurfaceView implements Callback{ 
 
    Bitmap bmp; 
    private Paint mPaint; 
    private SurfaceHolder mHolder; 
    public Surface(Context context) { 
        super(context); 
        mHolder = getHolder(); 
        mHolder.addCallback(this); 
        mPaint = new Paint(); 
        mPaint.setColor(Color.GREEN); 
        mPaint.setAntiAlias(true);//抗鋸齒 
        setFocusable(true); 
        setFocusableInTouchMode(true); 
//        setZOrderOnTop(true); 
//        mHolder.setFormat(PixelFormat.TRANSPARENT);//設置背景透明 
        bmp = BitmapFactory.decodeResource(getResources(), R.drawable.camera_r_local); 
        bmp = Bitmap.createScaledBitmap(bmp, 15, 15, false); 
    } 
 
    public Handler handler = new Handler(){ 
        @Override 
        public void handleMessage(Message msg) { 
            switch (msg.what) { 
            case 0: 
                canvas_ok(); 
                break; 
            } 
            super.handleMessage(msg); 
        } 
         
    }; 
     
    public void canvas_ok(){ 
         Canvas canvas = null; 
        try { 
            canvas = mHolder.lockCanvas(); 
            canvas.drawColor(Color.TRANSPARENT, Mode.CLEAR);//清除屏幕 
//          canvas.save(); 
            Matrix matrix = new Matrix(); 
            matrix.postTranslate(130, 0); 
            matrix.postRotate(degree, 130 ,130); 
            canvas.drawBitmap(bmp, matrix, mPaint); 
//          canvas.restore(); 
        } catch (Exception e) { 
        }finally { 
            if(canvas != null) { 
                mHolder.unlockCanvasAndPost(canvas); 
            } 
        } 
    } 
 
    int degree = 0; 
    Timer timer = new Timer(); 
    boolean flag = true; 
    @Override 
    public void surfaceCreated(SurfaceHolder holder) { 
        canvas_ok(); 
        timer.schedule(new TimerTask() { 
            @Override 
            public void run() { 
                if (flag) { 
                    degree++; 
                    if (degree == 360) { 
                        flag = false; 
                    } 
                }else { 
                    degree--; 
                    if(degree == -360 || degree == 0){ 
                        flag = true; 
                    } 
                } 
                Log.e("flag", degree+"  : "+flag); 
                handler.sendEmptyMessage(0); 
            } 
        }, 50, 50); 
    } 
 
 
    @Override 
    public void surfaceChanged(SurfaceHolder holder, int format, int width, 
            int height) { 
         
    } 
 
 
    @Override 
    public void surfaceDestroyed(SurfaceHolder holder) { 
        if (timer != null) { 
            timer.cancel(); 
            timer = null; 
        } 
    } 
} 

Main7.java是主類

[java]
package com.example.test; 
 
import android.app.Activity; 
import android.os.Bundle; 
import android.widget.RelativeLayout; 
 
public class Main7 extends Activity{ 
    Surface surface; 
    RelativeLayout.LayoutParams laParams; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        surface = new Surface(this); 
        laParams = new RelativeLayout.LayoutParams(260,  260); 
        setContentView(surface, laParams); 
    } 
 
}