在JavaScript中获取json对象的键[duplicate](get keys of json-object in JavaScript [duplicate])

 正如我所评论的，我写这个答案可能会帮助某人。这段代码只会在X轴上移动视图 
 
@Override
public boolean onTouch(View v, MotionEvent event) {

    switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN:
            dX = v.getX() - event.getRawX();
            dY = v.getY() - event.getRawY();
            lastAction = MotionEvent.ACTION_DOWN;
            break;

        case MotionEvent.ACTION_MOVE:
           //remove this v.setY() line
            v.setX(event.getRawX() + dX);
            lastAction = MotionEvent.ACTION_MOVE;
            break;

        case MotionEvent.ACTION_UP:
            if (lastAction == MotionEvent.ACTION_DOWN)
                Toast.makeText(MainActivity.this, "Clicked!", Toast.LENGTH_SHORT).show();
            break;

        default:
            return false;
    }
    return true;
}

Finally this problem is resolved by making some changes in my code.Hope this will help someone achieving this effect.
 
@Override
public boolean onTouch(View v, MotionEvent event) {

    switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN:
            dx = v.getX() - event.getRawX();
            dy = v.getY() - event.getRawY();
            ball_dx = ball.getX();
            lastAction = MotionEvent.ACTION_DOWN;
            break;

        case MotionEvent.ACTION_MOVE:
            //  ball.setY(event.getRawY() + dy);
            if ((event.getRawX() + dx + ball_dx) < screenwidth - 80 && (event.getRawX() + dx + ball_dx) > 10)
                ball.setX(event.getRawX() + dx + ball_dx);
            lastAction = MotionEvent.ACTION_MOVE;
            break;

        case MotionEvent.ACTION_UP:
            if (lastAction == MotionEvent.ACTION_DOWN)
                Toast.makeText(MainActivity.this, "Clicked!", Toast.LENGTH_SHORT).show();
            break;
        default:
            return false;
    }
    return true;
}