Question

我试图让一个Imageview（一个球）在布局周围移动并反弹多次，然后在按下按钮时停止。问题是虽然logcat说它发生了，但我看不出它在移动。

这是

public class BallPhisics {
int x =400;
int y = 0;
boolean bounceX = false;
boolean bounceY= false;
int counter =0;
ImageView object;
public BallPhisics(ImageView i){
    object=i;
}

public void applyMovement() {
    while (true) {
        object.setLeft((int) object.getX()+x); //i know i shouldnt use pixels
        Log.d("EVENT", "X moved");        Log.d("Ended",Integer.toString(object.getLeft()));

        object.setBottom((int)(object.getY() + y));
        Log.d("EVENT", "Y moved");
        try {
            Thread.sleep(1000);
            Log.d("EVENT", "Time 1 used");
        } catch(InterruptedException ex) {
            Thread.currentThread().interrupt();
        }

        if (object.getX()<=50||(object.getRight()<=50)){
            bounceX =true;
            break;
        }
        if (object.getY()<=50||object.getTop()<=50){
            bounceY=true;
            break;
        }
    }
    this.bouncing();

}
public void bouncing(){
    Log.d("EVENT", "Bouncing!!");
    if (bounceX&&bounceY){
        x=-x;
        y=-y;
    }
    else if (bounceX){
        x=-x;
        y=(int)(Math.random()*100- 50 +y);
    }
    else if (bounceY) {
        x = (int) (Math.random() * 100 - 50 + x);
        y = -y;
    }
    counter++;
    if(counter==5){return;}
    this.applyMovement();
}

在mainActivity上onclick事件。

 public void StartBall (View view){
    ImageView imageview=(ImageView) findViewById(R.id.imageView);
    BallPhisics phisics = new BallPhisics(imageview);
    Log.d("EVENT", Integer.toString(imageview.getLeft() )+" before");
    phisics.applyMovement();
    Log.d("EVENT",Integer.toString(imageview.getLeft())+" after" );

}

很抱歉，如果阅读很多。顺便说一下，有谁知道移动视图的正确方法？

提前致谢

Answer 1

首先移动视图使用setLeft (int left)或setBottom (int bottom)可能不是一个好主意，因为此方法应由布局系统调用，通常不应调用，{ {3}}

要动态移动视图，您应该查看LayoutParams或setX (float x)和setY (float Y)，如果您可以限制对Honeycomb（API级别11）的支持。

无论您使用哪一种，您都可能会发现难以实现平稳运动。因此，我建议您使用视图动画系统来执行ImageView的补间动画。

下面您将找到一个链动画示例，该动画使用任意y坐标从左向右移动ImageView。每次从一个x边框转换到下一个x边框后，将调用onAnimationEnd并在另一个方向上启动动画。

public class MainActivity extends Activity {

  //the ImageView you want to animate
  private ImageView imageview; 

  private Animation mAnimation;

  //The coordinates the view moved to in the last animation 
  private float lastX=0;
  private float lastY=0;
  private float secondlastY;

  //Listener that implements a translate animation chain
  AnimationListener animationListener=new AnimationListener() {
        @Override
        public void onAnimationEnd(Animation animation) {

            float newY=(float)(Math.random()*0.75);

            //this prevents that we move back to the position we came from
            // to get a more natural bounce animation
            while(newY<=secondlastY+0.15 && newY>=secondlastY-0.15){
                newY=(float)(Math.random()*0.75);
            }

            if(lastX==0.75f){
              //test if we are on the right border of the parent
                mAnimation=newAnimation(lastX,lastY,0f,newY);
                mAnimation.setAnimationListener(animationListener);
                lastX=0f;

            }else if(lastX==0.0f){
                //test if we are on the left border of the parent
                mAnimation=newAnimation(lastX,lastY,0.75f,newY);
                mAnimation.setAnimationListener(animationListener);
                lastX=0.75f;
            }

            secondlastY=lastY;
            lastY=newY;
            imageview.startAnimation(mAnimation);
        }
  };

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    imageview=(ImageView) findViewById(R.id.imageView);

    //the coordinates the first animation should move to
    lastY=(float)(Math.random()*0.75);
    lastX=0.75f;

    mAnimation=newAnimation(0f,0f,lastX,lastY); 
    mAnimation.setAnimationListener(animationListener);
    imageview.startAnimation(mAnimation);
 }

  //Method that returns a new animation with given start and end coordinates
  private Animation newAnimation(float startX, float startY, float endX, float endY){
     Animation mAnimation = new TranslateAnimation(
              TranslateAnimation.RELATIVE_TO_PARENT, startX,
              TranslateAnimation.RELATIVE_TO_PARENT, endX,
              TranslateAnimation.RELATIVE_TO_PARENT, startY,
              TranslateAnimation.RELATIVE_TO_PARENT, endY );
     mAnimation.setDuration(2500);
     mAnimation.setRepeatCount(0);
     mAnimation.setRepeatMode(Animation.REVERSE);
     mAnimation.setFillAfter(true);

     return mAnimation;
 }

}

注意：翻译动画相对于父母的宽度和高度。如果将“查看”一直移动到x = 1.0或y = 1.0，则会将视图的一部分移出父布局。因为这对于这个例子来说已经足够了，所以我选择将0.75设置为任一方向的最大位置。但是你应该根据ImageView和ParentLayout的宽度和高度动态设置它。

Imageview不动

1 个答案: