Android旋转动画

核心方法

public void startAnimation(Animation animation)

• 执行动画，参数可以是各种动画的对象，Animation的多态，也可以是组合动画，后面会有。

2个参数的构造方法

/**
 * Constructor to use when building a RotateAnimation from code.
 * Default pivotX/pivotY point is (0,0).
 * 
 * @param fromDegrees Rotation offset to apply at the start of the animation.
 * @param toDegrees Rotation offset to apply at the end of the animation.
 */
public RotateAnimation(float fromDegrees, float toDegrees) {
    mFromDegrees = fromDegrees;
    mToDegrees = toDegrees;
    mPivotX = 0.0f;
    mPivotY = 0.0f;
}

• 第一个参数是图片旋转的起始度数
• 第二个参数是图片旋转结束的度数

用法

RotateAnimation ta = new RotateAnimation(0, 360);
// 设置动画播放的时间
ta.setDuration(1000);
// 开始播放动画
iv.startAnimation(ta);

效果

以图片左上角为旋转中心，顺时针旋转360度

4个参数的构造方法

    /**
     * Constructor to use when building a RotateAnimation from code
     * 
     * @param fromDegrees Rotation offset to apply at the start of the animation.
     * @param toDegrees Rotation offset to apply at the end of the animation.
     * @param pivotX The X coordinate of the point about which the object is being rotated, specified as an absolute number where 0 is the left edge.
     * @param pivotY The Y coordinate of the point about which the object is being rotated, specified as an absolute number where 0 is the top edge.
     */
    public RotateAnimation(float fromDegrees, float toDegrees, float pivotX, float pivotY) {
        mFromDegrees = fromDegrees;
        mToDegrees = toDegrees;

        mPivotXType = ABSOLUTE;
        mPivotYType = ABSOLUTE;
        mPivotXValue = pivotX;
        mPivotYValue = pivotY;
        initializePivotPoint();
    }

• 头两个参数和上面两个参数的构造方法一样，是开始和结束的角度
• 后两个参数是设置图片的旋转中心

用法

RotateAnimation ta = new RotateAnimation(0, 360, iv.getWidth() / 2, iv.getHeight() / 2);
// 设置动画播放的时间
ta.setDuration(1000);
// 开始播放动画
iv.startAnimation(ta);

效果

以图片中心为旋转中心，顺时针旋转360度

6个参数的构造方法

/**
* Constructor to use when building a RotateAnimation from code
* 
* @param fromDegrees Rotation offset to apply at the start of the animation.
* @param toDegrees Rotation offset to apply at the end of the animation.
* @param pivotXType Specifies how pivotXValue should be interpreted. One of Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or Animation.RELATIVE_TO_PARENT.
* @param pivotXValue The X coordinate of the point about which the object is being rotated, specified as an absolute number where 0 is the left edge. This value can either be an absolute number if pivotXType is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise.
* @param pivotYType Specifies how pivotYValue should be interpreted. One of Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or Animation.RELATIVE_TO_PARENT.
* @param pivotYValue The Y coordinate of the point about which the object is being rotated, specified as an absolute number where 0 is the top edge. This value can either be an absolute number if pivotYType is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise.
*/
public RotateAnimation(float fromDegrees, float toDegrees, int pivotXType, float pivotXValue, int pivotYType, float pivotYValue) {
   mFromDegrees = fromDegrees;
   mToDegrees = toDegrees;

   mPivotXValue = pivotXValue;
   mPivotXType = pivotXType;
   mPivotYValue = pivotYValue;
   mPivotYType = pivotYType;
   initializePivotPoint();
}

• 比4个参数的构造方法多了第三个和第五个参数，其他用法一样，第三个和四五个参数分别设置第四个和第六个参数的类型，四个参数的构造没有设置，是默认设置了Animation.ABSOLUTE类型

用法

// 创建旋转的动画对象
RotateAnimation ta = new RotateAnimation(0, 360, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f);
// 设置动画播放的时间
ta.setDuration(1000);
// 开始播放动画
iv.startAnimation(ta);

效果

和上面一样，以图片中心为旋转中心，顺时针旋转360度。

设置动画重复播放的次数的方法

/**
 * Sets how many times the animation should be repeated. If the repeat
 * count is 0, the animation is never repeated. If the repeat count is
 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken
 * into account. The repeat count is 0 by default.
 *
 * @param repeatCount the number of times the animation should be repeated
 * @attr ref android.R.styleable#Animation_repeatCount
 */
public void setRepeatCount(int repeatCount) {
    if (repeatCount < 0) {
        repeatCount = INFINITE;
    }
    mRepeatCount = repeatCount;
}

使用

sa.setRepeatCount(2);

设置动画重复播放的模式的方法

/**
 * Defines what this animation should do when it reaches the end. This
 * setting is applied only when the repeat count is either greater than
 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 
 *
 * @param repeatMode {@link #RESTART} or {@link #REVERSE}
 * @attr ref android.R.styleable#Animation_repeatMode
 */
public void setRepeatMode(int repeatMode) {
    mRepeatMode = repeatMode;
}

使用

sa.setRepeatMode(ScaleAnimation.REVERSE);