Sliding Menu Demos 浅析：Custom Animation

Custom Animation：1、Zoom     

                             2、Scale

                             3、Slide Up

public abstract class CustomAnimation extends BaseActivity {
    
    private CanvasTransformer mTransformer;
    
    public CustomAnimation(int titleRes, CanvasTransformer transformer) {
        super(titleRes);
        mTransformer = transformer;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // set the Above View
        setContentView(R.layout.content_frame);
        getSupportFragmentManager()
        .beginTransaction()
        .replace(R.id.content_frame, new SampleListFragment())
        .commit();
        
        SlidingMenu sm = getSlidingMenu();
        setSlidingActionBarEnabled(true);
        sm.setBehindScrollScale(0.0f);
        sm.setBehindCanvasTransformer(mTransformer);
    }

}

主界面三个Demo使用的是一样的：在CustomAnimation设置Above View。

sm.setBehindCanvasTransformer(mTransformer);//Sets the behind canvas transformer.

动画效果主要是靠传入CanvasTransformer transformer这个接口来决定的。

public interface CanvasTransformer {

        /**
         * Transform canvas.
         *
         * @param 画布
         * @param open的百分比
         */
        public void transformCanvas(Canvas canvas, float percentOpen);
    }

ZOOM效果：

public class CustomZoomAnimation extends CustomAnimation {

    public CustomZoomAnimation() {
         super(R.string.anim_zoom, new CanvasTransformer() {//让父类来处理
            @Override
            //实现了接口
            public void transformCanvas(Canvas canvas, float percentOpen) {
                float scale = (float) (percentOpen*0.25 + 0.75);
                canvas.scale(scale, scale, canvas.getWidth()/2, canvas.getHeight()/2);
            }
        });
    }

}

canvas.scale(scale, scale, canvas.getWidth()/2, canvas.getHeight()/2)：

public final void scale(float sx, float sy, float px, float py) {
        translate(px, py);
        scale(sx, sy);
        translate(-px, -py);
    }

Scale：

public class CustomScaleAnimation extends CustomAnimation {

    public CustomScaleAnimation() {
        super(R.string.anim_scale, new CanvasTransformer() {
            @Override
            public void transformCanvas(Canvas canvas, float percentOpen) {
                canvas.scale(percentOpen, 1, 0, 0);
            }            
        });
    }

}

Slide up：（不同）

public class CustomSlideAnimation extends CustomAnimation {
    
    private static Interpolator interp = new Interpolator() {
        @Override
        public float getInterpolation(float t) {
            t -= 1.0f;
            return t * t * t + 1.0f;
        }        
    };

    public CustomSlideAnimation() {
        // see the class CustomAnimation for how to attach 
        // the CanvasTransformer to the SlidingMenu
        super(R.string.anim_slide, new CanvasTransformer() {
            @Override
            public void transformCanvas(Canvas canvas, float percentOpen) {
                canvas.translate(0, canvas.getHeight()*(1-interp.getInterpolation(percentOpen)));
            }            
        });
    }
}

Interpolator()：参考http://blog.csdn.net/jason0539/article/details/16370405

/**
 * interpolator定义了动画的刷新速度. 这就给动画实现加速，减速，重复等提供了可能 */
   public interface Interpolator extends TimeInterpolator {
    // A new interface, TimeInterpolator, was introduced for the new android.animation
    // package. This older Interpolator interface extends TimeInterpolator so that users of
    // the new Animator-based animations can use either the old Interpolator implementations or
    // new classes that implement TimeInterpolator directly.
}

  AccelerateDecelerateInterpolator 在动画开始与结束的地方速率改变比较慢，在中间的时候加速

  AccelerateInterpolator  在动画开始的地方速率改变比较慢，然后开始加速

  AnticipateInterpolator 开始的时候向后然后向前甩

  AnticipateOvershootInterpolator 开始的时候向后然后向前甩一定值后返回最后的值

  BounceInterpolator   动画结束的时候弹起

  CycleInterpolator 动画循环播放特定的次数，速率改变沿着正弦曲线

  DecelerateInterpolator 在动画开始的地方快然后慢

  LinearInterpolator   以常量速率改变

  OvershootInterpolator    向前甩一定值后再回到原来位置

  如果android定义的interpolators不符合你的效果也可以自定义interpolators