自定义SlideDetailsLayout控件的使用

使用场景：美工跟小姨子跑了，只能文字描述。
手机淘宝京东用过吧，商品详情页面进去之后，一般他有3个fragment切换展示：商品、详情、评价等等。商品那个fragment往下滑啊滑，滑到底部时候会有一个展示“上拉查看图文详情”之类的话，然后你继续滑一下，或者点一下那个view，哗啦~一下，详情那个fragment页面就会从商品fragment页面的底部顶出来，在整个页面展示。对！就这个使用场景。

使用方法：

布局文件：
使用SlideDetailsLayout包住fragment1的布局和fragment2的布局，其中fragment1的布局要用ScrollView包住。
（友情提示：搭配FloatingActionButton，效果更佳哟！~（同时CoordinatorLayout要作为主布局FloatingActionButton才有效））
页面代码：
1.1 SlideDetailsLayout设置OnSlideDetailsListener用来监听当前状态
1.2 设置开启smoothOpen()，smoothClose()；

public class SlideDetailsLayout extends ViewGroup {

public interface OnSlideDetailsListener {
    void onStatusChanged(Status status);
}

public enum Status {
    CLOSE,
    OPEN;

    public static Status valueOf(int stats) {
        if (0 == stats) {
            return CLOSE;
        } else if (1 == stats) {
            return OPEN;
        } else {
            return CLOSE;
        }
    }
}

private static final float DEFAULT_PERCENT = 0.2f;
private static final int DEFAULT_DURATION = 300;

private View mFrontView;
private View mBehindView;

private float mTouchSlop;
private float mInitMotionY;
private float mInitMotionX;


private View mTarget;
private float mSlideOffset;
private Status mStatus = Status.CLOSE;
private boolean isFirstShowBehindView = true;
private float mPercent = DEFAULT_PERCENT;
private long mDuration = DEFAULT_DURATION;
private int mDefaultPanel = 0;

private OnSlideDetailsListener mOnSlideDetailsListener;

public SlideDetailsLayout(Context context) {
    this(context, null);
}

public SlideDetailsLayout(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

public SlideDetailsLayout(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

    TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SlideDetailsLayout, defStyleAttr, 0);
    mPercent = a.getFloat(R.styleable.SlideDetailsLayout_percent, DEFAULT_PERCENT);
    mDuration = a.getInt(R.styleable.SlideDetailsLayout_duration, DEFAULT_DURATION);
    mDefaultPanel = a.getInt(R.styleable.SlideDetailsLayout_default_panel, 0);
    a.recycle();

    mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
}

public void setOnSlideDetailsListener(OnSlideDetailsListener listener) {
    this.mOnSlideDetailsListener = listener;
}

public void smoothOpen(boolean smooth) {
    if (mStatus != Status.OPEN) {
        mStatus = Status.OPEN;
        final float height = -getMeasuredHeight();
        animatorSwitch(0, height, true, smooth ? mDuration : 0);
    }
}

public void smoothClose(boolean smooth) {
    if (mStatus != Status.CLOSE) {
        mStatus = Status.CLOSE;
        final float height = -getMeasuredHeight();
        animatorSwitch(height, 0, true, smooth ? mDuration : 0);
    }
}

public void setPercent(float percent) {
    this.mPercent = percent;
}

@Override
protected LayoutParams generateDefaultLayoutParams() {
    return new MarginLayoutParams(MarginLayoutParams.WRAP_CONTENT, MarginLayoutParams.WRAP_CONTENT);
}

@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
    return new MarginLayoutParams(getContext(), attrs);
}

@Override
protected LayoutParams generateLayoutParams(LayoutParams p) {
    return new MarginLayoutParams(p);
}

@Override
protected void onFinishInflate() {
    super.onFinishInflate();

    final int childCount = getChildCount();
    if (1 >= childCount) {
        throw new RuntimeException("SlideDetailsLayout only accept childs more than 1!!");
    }

    mFrontView = getChildAt(0);
    mBehindView = getChildAt(1);
    if (mDefaultPanel == 1) {
        post(new Runnable() {
            @Override
            public void run() {
                smoothOpen(false);
            }
        });
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    final int pWidth = MeasureSpec.getSize(widthMeasureSpec);
    final int pHeight = MeasureSpec.getSize(heightMeasureSpec);

    final int childWidthMeasureSpec =
            MeasureSpec.makeMeasureSpec(pWidth, MeasureSpec.EXACTLY);
    final int childHeightMeasureSpec =
            MeasureSpec.makeMeasureSpec(pHeight, MeasureSpec.EXACTLY);

    View child;
    for (int i = 0; i < getChildCount(); i++) {
        child = getChildAt(i);
        if (child.getVisibility() == GONE) {
            continue;
        }

        measureChild(child, childWidthMeasureSpec, childHeightMeasureSpec);
    }

    setMeasuredDimension(pWidth, pHeight);
}

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    final int left = l;
    final int right = r;
    int top;
    int bottom;

    final int offset = (int) mSlideOffset;

    View child;
    for (int i = 0; i < getChildCount(); i++) {
        child = getChildAt(i);
        if (child.getVisibility() == GONE) {
            continue;
        }
        if (child == mBehindView) {
            top = b + offset;
            bottom = top + b - t;
        } else {
            top = t + offset;
            bottom = b + offset;
        }
        child.layout(left, top, right, bottom);
    }
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
    ensureTarget();
    if (null == mTarget) {
        return false;
    }

    if (!isEnabled()) {
        return false;
    }

    final int aciton = MotionEventCompat.getActionMasked(ev);

    boolean shouldIntercept = false;
    switch (aciton) {
        case MotionEvent.ACTION_DOWN: {
            mInitMotionX = ev.getX();
            mInitMotionY = ev.getY();
            shouldIntercept = false;
            break;
        }
        case MotionEvent.ACTION_MOVE: {
            final float x = ev.getX();
            final float y = ev.getY();

            final float xDiff = x - mInitMotionX;
            final float yDiff = y - mInitMotionY;

            if (canChildScrollVertically((int) yDiff)) {
                shouldIntercept = false;
            } else {
                final float xDiffabs = Math.abs(xDiff);
                final float yDiffabs = Math.abs(yDiff);

                if (yDiffabs > mTouchSlop && yDiffabs >= xDiffabs
                        && !(mStatus == Status.CLOSE && yDiff > 0
                        || mStatus == Status.OPEN && yDiff < 0)) {
                    shouldIntercept = true;
                }
            }
            break;
        }
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL: {
            shouldIntercept = false;
            break;
        }
    }
    return shouldIntercept;
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
    ensureTarget();
    if (null == mTarget) {
        return false;
    }
    if (!isEnabled()) {
        return false;
    }
    boolean wantTouch = true;
    final int action = MotionEventCompat.getActionMasked(ev);

    switch (action) {
        case MotionEvent.ACTION_DOWN: {
            if (mTarget instanceof View) {
                wantTouch = true;
            }
            break;
        }

        case MotionEvent.ACTION_MOVE: {
            final float y = ev.getY();
            final float yDiff = y - mInitMotionY;
            if (canChildScrollVertically(((int) yDiff))) {
                wantTouch = false;
            } else {
                processTouchEvent(yDiff);
                wantTouch = true;
            }
            break;
        }

        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL: {
            finishTouchEvent();
            wantTouch = false;
            break;
        }
    }
    return wantTouch;
}

private void processTouchEvent(final float offset) {
    if (Math.abs(offset) < mTouchSlop) {
        return;
    }

    final float oldOffset = mSlideOffset;
    if (mStatus == Status.CLOSE) {
        // reset if pull down
        if (offset >= 0) {
            mSlideOffset = 0;
        } else {
            mSlideOffset = offset;
        }

        if (mSlideOffset == oldOffset) {
            return;
        }

    } else if (mStatus == Status.OPEN) {
        final float pHeight = -getMeasuredHeight();
        if (offset <= 0) {
            mSlideOffset = pHeight;
        } else {
            final float newOffset = pHeight + offset;
            mSlideOffset = newOffset;
        }

        if (mSlideOffset == oldOffset) {
            return;
        }
    }
    requestLayout();
}

private void finishTouchEvent() {
    final int pHeight = getMeasuredHeight();
    final int percent = (int) (pHeight * mPercent);
    final float offset = mSlideOffset;

    boolean changed = false;

    if (Status.CLOSE == mStatus) {
        if (offset <= -percent) {
            mSlideOffset = -pHeight;
            mStatus = Status.OPEN;
            changed = true;
        } else {
            mSlideOffset = 0;
        }
    } else if (Status.OPEN == mStatus) {
        if ((offset + pHeight) >= percent) {
            mSlideOffset = 0;
            mStatus = Status.CLOSE;
            changed = true;
        } else {
            mSlideOffset = -pHeight;
        }
    }

    animatorSwitch(offset, mSlideOffset, changed);
}

private void animatorSwitch(final float start, final float end) {
    animatorSwitch(start, end, true, mDuration);
}

private void animatorSwitch(final float start, final float end, final long duration) {
    animatorSwitch(start, end, true, duration);
}

private void animatorSwitch(final float start, final float end, final boolean changed) {
    animatorSwitch(start, end, changed, mDuration);
}

private void animatorSwitch(final float start,
                            final float end,
                            final boolean changed,
                            final long duration) {
    ValueAnimator animator = ValueAnimator.ofFloat(start, end);
    animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            mSlideOffset = (float) animation.getAnimatedValue();
            requestLayout();
        }
    });
    animator.addListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            super.onAnimationEnd(animation);
            if (changed) {
                if (mStatus == Status.OPEN) {
                    checkAndFirstOpenPanel();
                }

                if (null != mOnSlideDetailsListener) {
                    mOnSlideDetailsListener.onStatusChanged(mStatus);
                }
            }
        }
    });
    animator.setDuration(duration);
    animator.start();
}

private void checkAndFirstOpenPanel() {
    if (isFirstShowBehindView) {
        isFirstShowBehindView = false;
        mBehindView.setVisibility(VISIBLE);
    }
}

private void ensureTarget() {
    if (mStatus == Status.CLOSE) {
        mTarget = mFrontView;
    } else {
        mTarget = mBehindView;
    }
}

protected boolean canChildScrollVertically(int direction) {
    if (mTarget instanceof AbsListView) {
        return canListViewSroll((AbsListView) mTarget);
    } else if (mTarget instanceof FrameLayout ||
            mTarget instanceof RelativeLayout ||
            mTarget instanceof LinearLayout) {
        View child;
        for (int i = 0; i < ((ViewGroup) mTarget).getChildCount(); i++) {
            child = ((ViewGroup) mTarget).getChildAt(i);
            if (child instanceof AbsListView) {
                return canListViewSroll((AbsListView) child);
            }
        }
    }

    if (android.os.Build.VERSION.SDK_INT < 14) {
        return ViewCompat.canScrollVertically(mTarget, -direction) || mTarget.getScrollY() > 0;
    } else {
        return ViewCompat.canScrollVertically(mTarget, -direction);
    }
}

protected boolean canListViewSroll(AbsListView absListView) {
    if (mStatus == Status.OPEN) {
        return absListView.getChildCount() > 0
                && (absListView.getFirstVisiblePosition() > 0 || absListView.getChildAt(0)
                .getTop() <
                absListView.getPaddingTop());
    } else {
        final int count = absListView.getChildCount();
        return count > 0
                && (absListView.getLastVisiblePosition() < count - 1
                || absListView.getChildAt(count - 1)
                .getBottom() > absListView.getMeasuredHeight());
    }
}

@Override
protected Parcelable onSaveInstanceState() {
    SavedState ss = new SavedState(super.onSaveInstanceState());
    ss.offset = mSlideOffset;
    ss.status = mStatus.ordinal();
    return ss;
}

@Override
protected void onRestoreInstanceState(Parcelable state) {
    SavedState ss = (SavedState) state;
    super.onRestoreInstanceState(ss.getSuperState());
    mSlideOffset = ss.offset;
    mStatus = Status.valueOf(ss.status);

    if (mStatus == Status.OPEN) {
        mBehindView.setVisibility(VISIBLE);
    }

    requestLayout();
}

static class SavedState extends BaseSavedState {

    private float offset;
    private int status;

    public SavedState(Parcel source) {
        super(source);
        offset = source.readFloat();
        status = source.readInt();
    }

    public SavedState(Parcelable superState) {
        super(superState);
    }

    @Override
    public void writeToParcel(Parcel out, int flags) {
        super.writeToParcel(out, flags);
        out.writeFloat(offset);
        out.writeInt(status);
    }

    public static final Creator<SavedState> CREATOR =
            new Creator<SavedState>() {
                public SavedState createFromParcel(Parcel in) {
                    return new SavedState(in);
                }

                public SavedState[] newArray(int size) {
                    return new SavedState[size];
                }
            };
}

}

最后编辑于：2017.12.09 18:23:57

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自定义SlideDetailsLayout控件的使用

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