android 图片拖动简单例子

package com.xf;import android.app.Activity;import android.os.Bundle;import android.util.DisplayMetrics;import android.view.MotionEvent;import android.view.View;import android.view.View.OnTouchListener;import android.widget.ImageView;public class XFActivity extends Activity implements OnTouchListener{private ImageView iv;//拖动用的图片int x,y;//图片上一个的XY位置int screenWidth,screenHeight;//当前屏幕的宽度和高度（像素表示）    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                DisplayMetrics dm = getResources().getDisplayMetrics();         screenWidth = dm.widthPixels;         screenHeight = dm.heightPixels;                 iv=(ImageView)findViewById(R.id.im);        iv.setOnTouchListener(this);    }@Overridepublic boolean onTouch(View v, MotionEvent e) {System.out.println(e.getAction());switch(e.getAction()){case MotionEvent.ACTION_DOWN://按下//获取按下时的X,Y轴位置  x = (int) e.getRawX();            y = (int) e.getRawY();break;case MotionEvent.ACTION_UP://松开break;case MotionEvent.ACTION_MOVE://执行 ACTION_DOWN 才执行 ACTION_MOVEint mX = (int)e.getRawX()-x;int mY = (int)e.getRawY()-y;int left = v.getLeft()+mX;int top = v.getTop()+mY;int right = v.getRight()+mX;int bottom = v.getBottom()+mY;  // 设置不能出界                 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);//记住手指滑动所在的X,Y轴位置，也就是上一个X,Y轴的位置x = (int) e.getRawX();                  y = (int) e.getRawY(); break;}return true;}}
更多相关文章

随机推荐
