安卓控件拖动

/**

此文主要有两大要点

1.控件的拖动

2.控件同时实现点击事件与拖动事件时的冲突处理

要点地方都有注释

*/

public class extents Activity{

/** Called when the activity is first created. */

private long startTime = 0;
private long endTime = 0;
private boolean isclick;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

// 获取屏幕的宽高
DisplayMetrics dm = getResources().getDisplayMetrics();
final int screenWidth = dm.widthPixels;
final int screenHeight = dm.heightPixels - 50;

final Button b=(Button)findViewById(R.id.btn);

b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
              
            }
        });

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();

isclick = false;//当按下的时候设置isclick为false
startTime = System.currentTimeMillis();

break;

case MotionEvent.ACTION_MOVE:

isclick = true;//当按钮被移动的时候设置isclick为true??

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;

/*

此处是为了防止滑出界面

*/

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:

endTime = System.currentTimeMillis();
                //当从点击到弹起小于半秒的时候,则判断为点击,如果超过则不响应点击事件??
                if ((endTime - startTime) > 0.1 * 1000L) {
                    isclick = true;
                } else {
                    isclick = false;
                }

break;        
}
return isclick;
}});
}
}