Android 根据滑动平移控件 android拖动控件效果

Android拖动实现很简单，主要就是实现OnTouchListener事件监听，获取到触碰点之后，重新设置View的位置即可。

下面是这个例子的描述：

首先点击create按钮，将会产生一个新的ImageView对象，然后移动新的ImageView到任何你想要去的地方。

下面是源码：

创建一个新的View，并添加到Window中：

package com.mandr.test;
import android.content.Context;
 import android.util.DisplayMetrics;
 import android.util.Log;
 import android.view.Gravity;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.WindowManager;
 import android.view.View.OnTouchListener;
 import android.widget.ImageView;
 import android.widget.LinearLayout;public class CreatView {
  public static final String Tag = "CreatView";private Context mContext;
  protected static CreatView mCreatView;
  private int[] location;
  private ImageView mImageView;
  public WindowManager mWm;
  public WindowManager.LayoutParams layoutParams;public CreatView(Context context) {
   this.mContext = context;
   mWm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
   layoutParams = new WindowManager.LayoutParams();
  }public synchronized static CreatView getCreatView(Context context) {
   Log.d(Tag, "getCreatView");
   if (mCreatView == null) {
    mCreatView = new CreatView(context);
   }
   return mCreatView;
  }public void setLocation(int[] location) {
   this.location = location;
  }private View createNewView() {
   Log.d(Tag, "createNewView");
   ImageView mImageView = new ImageView(mContext);
   mImageView.setImageDrawable(mContext.getResources().getDrawable(
     R.drawable.apple));
   mImageView.setLayoutParams(new LinearLayout.LayoutParams(40, 40));
   return mImageView;
  }public void addViewToScreen() {
   Log.d(Tag, "addViewToScreen");
   mImageView = (ImageView) createNewView();
   mImageView.setOnTouchListener(new TouchListener()); layoutParams.gravity = Gravity.LEFT | Gravity.TOP;
   layoutParams.x = location[0] + 30; //偏移量x
   layoutParams.y = location[1];      //偏移量y
   layoutParams.width = 40;
   layoutParams.height = 40;
   layoutParams.alpha = 1.0f;
   mWm.addView(mImageView, layoutParams);
  }class TouchListener implements OnTouchListener {
 int lastX;
   int lastY;
   int screenWidth;
   int screenHeight; public TouchListener() {
    DisplayMetrics dm = mContext.getResources().getDisplayMetrics();
    screenWidth = dm.widthPixels;
    screenHeight = dm.heightPixels;
    Log.d(Tag, "screen width =" + screenWidth + ",screen height="
      + screenHeight);
   } @Override
   public boolean onTouch(View v, MotionEvent event) {
    Log.d(Tag, "TouchListener -- onTouch");
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
     lastX = (int) event.getRawX();
     lastY = (int) event.getRawY();
     Log.d(Tag, "down x=" + lastX + ", y=" + lastY);
     break;
    case MotionEvent.ACTION_MOVE:
     int dx = (int) event.getRawX() - lastX;
     int dy = (int) event.getRawY() - lastY;
     Log.d(Tag, "move dx=" + dx + ",  dy=" + dy);
     int left = v.getLeft() + dx;
     int top = v.getTop() + dy;
     int right = v.getRight() + dx;
     int bottom = v.getBottom() + dy;
     Log.d(Tag, "view  left=" + left + ", top=" + top + ", right="
       + right + ",bottom=" + bottom);
     // set bound
     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);
     lastX = (int) event.getRawX();
     lastY = (int) event.getRawY();
     layoutParams.x = lastX;
     layoutParams.y = lastY-30;
     mWm.updateViewLayout(v, layoutParams);
     
     lastX = (int) event.getRawX();
     lastY = (int) event.getRawY();
     break;
    case MotionEvent.ACTION_UP:
     break;
    }
    return true;
   }
  }
 }

测试的Activity：

package com.mandr.test;
import android.app.Activity;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.Button;public class MainActivity extends Activity {
     public static final String  Tag = "MainActivity";
    
     private Button creatorBtn;
     private CreatView mCreatView;
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         mCreatView = CreatView.getCreatView(this);
        
         creatorBtn = (Button)this.findViewById(R.id.button1);
         creatorBtn.setOnClickListener(new View.OnClickListener() {
    
    @Override
    public void onClick(View v) {
     Log.d(Tag, "creatorBtn  click");
     int[] location = new int[2];
     v.getLocationInWindow(location);
     Log.d(Tag, "x = "+location[0]+",y = "+location[1]);
     mCreatView.setLocation(location);
     mCreatView.addViewToScreen();
    }
   });
     }
 }