Question

我有以下问题：我在android上创建了一个自定义视图。我想通过缩放动画（pivotX =“50％”和pivotY =“50％”）来制作视图脉冲。如果视图位于屏幕中间，则缩放工作正常。如果视图位于屏幕的左侧，则看起来pivotX值将为“75％”。如果视图位于屏幕的右侧，则看起来pivotX值将为“25％”。

以下是我的观点代码：

public class TestView extends View
{
  private Paint _paint = new Paint();

  private int _x, _y;

  public TestView( Context context, int x, int y )
  {
    super( context );

    _x = x;
    _y = y;

    _paint.setAntiAlias( true );
    _paint.setColor( Color.BLUE );
    _paint.setStyle( Style.FILL );
  }

  @Override
  protected void onDraw( Canvas canvas )
  {
    super.onDraw( canvas );
    canvas.drawCircle( _x, _y, 100 , _paint );
  }
}

以下是动画pulse.xml文件的代码：

<scale xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="100"
android:fromXScale="1"
android:fromYScale="1"
android:pivotX="50%"
android:pivotY="50%"
android:repeatCount="3"
android:repeatMode="reverse"
android:toXScale="1.7"
android:toYScale="1.7" >
</scale>

片段类的代码：

ViewGroup mainLayout = (ViewGroup) getView().findViewById( R.id.my_layout );    

float y = screenHeigth / 2;

float x1 = screenWidth*3/4; // right hand side of the screen
dest1 = new TestView( getActivity(), x1, y );
mainLayout.addView( dest1 );

float x2 = screenWidth / 2; // in the middle of the screen
dest2 = new TestView( getActivity(), x2, y );
mainLayout.addView( dest2 );

float x3 = screenWidth / 4; // left hand side of the screen
dest3 = new TestView( getActivity(), x3, y );
mainLayout.addView( dest3 );

ScaleAnimation pulse = (ScaleAnimation) AnimationUtils.loadAnimation( getActivity(), R.anim.pulse );

dest1.startAnimation( pulse );
dest2.startAnimation( pulse );
dest3.startAnimation( pulse );

我做错了什么？也许我必须在我的TestView类中做一些事情？

Answer 1

现在我知道了:-)谢谢你pskink带我走正确的道路。问题是，我的TestView填充了整个父视图。因此，我视图的中心是父视图的中心，而不是绘制圆的中心。

以下是解决方案：

public class TestView extends View
{
  private Paint _paint = new Paint();

  private int _xRelativeToView, _yRelativeToView, _w, _radius;

  public TestView( Context context, int xOfView, int yOfView )
  {
    super( context );

    _w = 100;
    _radius = _w / 2;

    // set the coordinates of the circle within this view
    _xRelativeToView = _radius;
    _yRelativeToView = _radius;

    // set the position of the view on the screen:
    LayoutParams mparam = new LayoutParams( _w, _w ); // the view is as big as the circle
    mparam.addRule( RelativeLayout.ALIGN_PARENT_LEFT );
    mparam.setMargins( xOfView - _radius, yOfView - _radius, 0, 0 );
    setLayoutParams( mparam );

    // initialize paint
    _paint.setAntiAlias( true );
    _paint.setColor( Color.BLUE );
    _paint.setStyle( Style.FILL );
  }

  @Override
  protected void onDraw( Canvas canvas )
  {
    super.onDraw( canvas );
    canvas.drawCircle( _xRelativeToView, _yRelativeToView, _radius, _paint );
  }
}

自定义视图上的缩放动画在未放置在屏幕中间时表现错误

1 个答案: