自定义View,在onDraw()方法中绘制一条直线,在onTouch()方法中监听手指的移动。
public class AroundDragView extends View implements View.OnTouchListener {
private static final String TAG = "ImageLight";
protected int screenWidth;
protected int screenHeight;
protected int lastX;
protected Paint paint = new Paint();
int offset = 30;public AroundDragView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
setOnTouchListener(this);
}
public AroundDragView(Context context, AttributeSet attrs) {
super(context, attrs);
setOnTouchListener(this);
}
public AroundDragView(Context context) {
super(context);
setOnTouchListener(this);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
paint.setColor(Color.YELLOW);
paint.setStrokeWidth(4.0f);
paint.setStyle(Paint.Style.STROKE);
canvas.drawLine(offset / 2, 0, offset / 2, getHeight(), paint);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
oriLeft = v.getLeft();
oriRight = v.getRight();
lastX = (int) event.getRawX();
break;
case MotionEvent.ACTION_MOVE:
int dx = (int) event.getRawX() - lastX;
move(v, dx);
lastX = (int) event.getRawX();
break;
case MotionEvent.ACTION_UP:
break;
}
invalidate();
return false;
}
/**
* 移动
*
* @param v
* @param dx
*/
private void move(View v, int dx) {
int left = v.getLeft() + dx;
int right = v.getRight() + dx;
if (left < 100 + offset) {
left = 100 + offset;
right = left + v.getWidth();
}
if (right > screenWidth - 100) {
right = screenWidth - 100;
left = right - v.getWidth();
}
v.layout(left, 0, right, getHeight());
}
}
将上面的View作为一个View放在XML文件中即可,例如:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<com.desmand.utils.AroundDragView
android:id="@+id/video_around_drag_view"
android:layout_width="20dp"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:clickable="true"/>
</RelativeLayout>