ScrollView反弹效果 仿小米私密短信效果 android布局可滚动

<com.bignerdranch.android.xundian.ui.BounceScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:background="@color/colorAccent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/id_scrollView">

<LinearLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorAccent">

</LinearLayout></com.bignerdranch.android.xundian.ui.BounceScrollView>

/*** Created by Administrator on 2017/9/11.*/import android.content.Context;import android.graphics.Rect;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.animation.Animation;import android.view.animation.TranslateAnimation;import android.widget.ScrollView;/*** 支持上下反弹效果的ScrollView** @author zhy**/public class BounceScrollView extends ScrollView{private boolean isCalled ;private Callback mCallback;/*** 包含的View*/private View mView;/*** 存储正常时的位置*/private Rect mRect = new Rect();/*** y坐标*/private int y;private boolean isFirst = true;public BounceScrollView(Context context, AttributeSet attrs){super(context, attrs);}/**** 根据 XML 生成视图工作完成.该函数在生成视图的最后调用，在所有子视图添加完之后. 即使子类覆盖了 onFinishInflate* 方法，也应该调用父类的方法，使该方法得以执行.*/@Overrideprotected void onFinishInflate(){if (getChildCount() > 0)mView = getChildAt(0);super.onFinishInflate();}@Overridepublic boolean onTouchEvent(MotionEvent ev){if (mView != null){commonOnTouch(ev);}return super.onTouchEvent(ev);}private void commonOnTouch(MotionEvent ev){int action = ev.getAction();int cy = (int) ev.getY();switch (action){case MotionEvent.ACTION_DOWN:break;/*** 跟随手指移动*/case MotionEvent.ACTION_MOVE:int dy = cy - y;if (isFirst){dy = 0;isFirst = false;}y = cy;if (isNeedMove()){if (mRect.isEmpty()){/*** 记录移动前的位置*/mRect.set(mView.getLeft(), mView.getTop(),mView.getRight(), mView.getBottom());}mView.layout(mView.getLeft(), mView.getTop() + 2 * dy / 3,mView.getRight(), mView.getBottom() + 2 * dy / 3);if (shouldCallBack(dy)){if (mCallback != null){if(!isCalled){isCalled = true ;resetPosition();mCallback.callback();}}}}break;/*** 反弹回去*/case MotionEvent.ACTION_UP:if (!mRect.isEmpty()){resetPosition();}break;}}/*** 当从上往下，移动距离达到一半时，回调接口** @return*/private boolean shouldCallBack(int dy){if (dy > 0 && mView.getTop() > getHeight() / 2)return true;return false;}private void resetPosition(){Animation animation = new TranslateAnimation(0, 0, mView.getTop(),mRect.top);animation.setDuration(200);animation.setFillAfter(true);mView.startAnimation(animation);mView.layout(mRect.left, mRect.top, mRect.right, mRect.bottom);mRect.setEmpty();isFirst = true;isCalled = false ;}/**** 是否需要移动布局 inner.getMeasuredHeight():获取的是控件的总高度** getHeight()：获取的是屏幕的高度** @return*/public boolean isNeedMove(){int offset = mView.getMeasuredHeight() - getHeight();int scrollY = getScrollY();// 0是顶部，后面那个是底部if (scrollY == 0 || scrollY == offset){return true;}return false;}public void setCallBack(Callback callback){mCallback = callback;}interface Callback{void callback();}}