android 个人中心下拉弹回效果 |
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android 个人中心下拉弹回效果
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实现效果：
这个效果就是仿qq个人中心的下拉弹回效果实现。 核心就是一个 自定义的ScrollView，如下： package com.baobao.testpullscrollview; import android.annotation.SuppressLint; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Rect; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.animation.TranslateAnimation; import android.widget.ScrollView; public class PullScrollView extends ScrollView { /** 阻尼系数,越小阻力就越大. */ private static final float SCROLL_RATIO = 0.5f; /** 滑动至翻转的距离. */ private static final int TURN_DISTANCE = 100; /** 头部view. */ private View mHeader; /** 头部view高度. */ private int mHeaderHeight; /** 头部view显示高度. */ private int mHeaderVisibleHeight; /** ScrollView的content view. */ private View mContentView; /** ScrollView的content view矩形. */ private Rect mContentRect = new Rect(); /** 首次点击的Y坐标. */ private float mTouchDownY; /** 是否关闭ScrollView的滑动. */ private boolean mEnableTouch = false; /** 是否开始移动. */ private boolean isMoving = false; /** 是否移动到顶部位置. */ private boolean isTop = false; /** 头部图片初始顶部和底部. */ private int mInitTop, mInitBottom; /** 头部图片拖动时顶部和底部. */ private int mCurrentTop, mCurrentBottom; /** 状态变化时的监听器. */ private OnTurnListener mOnTurnListener; private enum State { /**顶部*/ UP, /**底部*/ DOWN, /**正常*/ NORMAL } /** 状态. */ private State mState = State.NORMAL; public PullScrollView(Context context) { super(context); init(context, null); } public PullScrollView(Context context, AttributeSet attrs) { super(context, attrs); init(context, attrs); } public PullScrollView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(context, attrs); } @SuppressLint("NewApi") private void init(Context context, AttributeSet attrs) { // set scroll mode setOverScrollMode(OVER_SCROLL_NEVER); if (null != attrs) { TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.PullScrollView); if (ta != null) { mHeaderHeight = (int) ta.getDimension(R.styleable.PullScrollView_headerHeight, -1); mHeaderVisibleHeight = (int) ta.getDimension(R.styleable .PullScrollView_headerVisibleHeight, -1); ta.recycle(); } } } /** * 设置Header * * @param view */ public void setHeader(View view) { mHeader = view; } /** * 设置状态改变时的监听器 * * @param turnListener */ public void setOnTurnListener(OnTurnListener turnListener) { mOnTurnListener = turnListener; } @Override protected void onFinishInflate() { if (getChildCount() > 0) { mContentView = getChildAt(0); } } @Override protected void onScrollChanged(int l, int t, int oldl, int oldt) { super.onScrollChanged(l, t, oldl, oldt); if (getScrollY() == 0) { isTop = true; } } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if (ev.getAction() == MotionEvent.ACTION_DOWN) { mTouchDownY = ev.getY(); mCurrentTop = mInitTop = mHeader.getTop(); mCurrentBottom = mInitBottom = mHeader.getBottom(); } return super.onInterceptTouchEvent(ev); } @Override public boolean onTouchEvent(MotionEvent ev) { if (mContentView != null) { doTouchEvent(ev); } // 禁止控件本身的滑动. return mEnableTouch || super.onTouchEvent(ev); } /** * 触摸事件处理 * * @param event */ private void doTouchEvent(MotionEvent event) { int action = event.getAction(); switch (action) { case MotionEvent.ACTION_MOVE: doActionMove(event); break; case MotionEvent.ACTION_UP: // 回滚动画 if (isNeedAnimation()) { rollBackAnimation(); } if (getScrollY() == 0) { mState = State.NORMAL; } isMoving = false; mEnableTouch = false; break; default: break; } } /** * 执行移动动画 * * @param event */ private void doActionMove(MotionEvent event) { // 当滚动到顶部时，将状态设置为正常，避免先向上拖动再向下拖动到顶端后首次触摸不响应的问题 if (getScrollY() == 0) { mState = State.NORMAL; // 滑动经过顶部初始位置时，修正Touch down的坐标为当前Touch点的坐标 if (isTop) { isTop = false; mTouchDownY = event.getY(); } } float deltaY = event.getY() - mTouchDownY; // 对于首次Touch操作要判断方位：UP OR DOWN if (deltaY < 0 && mState == State.NORMAL) { mState = State.UP; } else if (deltaY > 0 && mState == State.NORMAL) { mState = State.DOWN; } if (mState == State.UP) { deltaY = deltaY < 0 ? deltaY : 0; isMoving = false; mEnableTouch = false; } else if (mState == State.DOWN) { if (getScrollY() |
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