android 随意拖动的view

import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ImageView;
import com.dsy.tui.tools.JavaTools;

/**
 *随意拖动的view
 */

@SuppressLint("AppCompatCustomView")
public class DragView extends ImageView {

    private int width;
    private int height;
    private int screenWidth;
    private int screenHeight;
    private Context context;

    //是否拖动
    private boolean isDrag=false;

    public boolean isDrag() {
        return isDrag;
    }
    public DragView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context=context;
    }
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width=getMeasuredWidth();
        height=getMeasuredHeight();
        screenWidth= JavaTools.getDispaly(context).widthPixels;
        screenHeight= JavaTools.getDispaly(context).heightPixels;

    }
    public int getStatusBarHeight(){
        int resourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
        return getResources().getDimensionPixelSize(resourceId);
    }


    private float downX;
    private float downY;


    @Override
    public boolean onTouchEvent(MotionEvent event) {
        super.onTouchEvent(event);
        if (this.isEnabled()) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    isDrag=false;
                    downX = event.getX();
                    downY = event.getY();
                    break;
                case MotionEvent.ACTION_MOVE:
                    Log.e("kid","ACTION_MOVE");
                    final float xDistance = event.getX() - downX;
                    final float yDistance = event.getY() - downY;
                    int l,r,t,b;
                    //当水平或者垂直滑动距离大于10,才算拖动事件
                    if (Math.abs(xDistance) >10 ||Math.abs(yDistance)>10) {
                        Log.e("kid","Drag");
                        isDrag=true;
                         l = (int) (getLeft() + xDistance);
                         r = l+width;
                         t = (int) (getTop() + yDistance);
                         b = t+height;
                        //不划出边界判断,此处应按照项目实际情况,因为本项目需求移动的位置是手机全屏,
                        // 所以才能这么写,如果是固定区域,要得到父控件的宽高位置后再做处理
                        if(l<0){
                            l=0;
                            r=l+width;
                        }else if(r>screenWidth){
                            r=screenWidth;
                            l=r-width;
                        }
                        if(t<0){
                            t=0;
                            b=t+height;
                        }else if(b>screenHeight){
                            b=screenHeight;
                            t=b-height;
                        }

                        this.layout(l, t, r, b);
                    }
                    break;
                case MotionEvent.ACTION_UP:
                    setPressed(false);
                    break;
                case MotionEvent.ACTION_CANCEL:
                    setPressed(false);
                    break;
            }
            return true;
        }
        return false;
    }

}

获取手机屏幕的宽高

import android.content.Context;
import android.util.DisplayMetrics;

/**
 * @Description: 
 */
public class JavaTools {

    public static DisplayMetrics getDispaly(Context context){
        DisplayMetrics dm = new DisplayMetrics();
        dm = context.getResources().getDisplayMetrics();
        float density = dm.density; // 屏幕密度（像素比例：0.75/1.0/1.5/2.0）
        int densityDPI = dm.densityDpi; // 屏幕密度（每寸像素：120/160/240/320）
        float xdpi = dm.xdpi;
        float ydpi = dm.ydpi;
//        screenWidth = dm.widthPixels; // 屏幕宽（像素，如：480px）
//        screenHeight = dm.heightPixels; // 屏幕高（像素，如：800px）
        return dm;
    }
}

最后一步就和使用控件一样使用就可以了