自适应文字列表布局

package com.app.hero.ui.live.adapter;import android.content.Context;import android.graphics.Rect;import android.support.v4.util.SparseArrayCompat;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.RecyclerView.LayoutManager;import android.view.View;import android.view.ViewGroup;/** * Created on 2017/9/19. */public class AutoTextContentLayoutManager extends LayoutManager {    private int mTotalHeight;    private int mVerticalOffset;    private Pool<Rect> mItemFrames;    public AutoTextContentLayoutManager(Context context) {        super();        setAutoMeasureEnabled(true);        mItemFrames = new Pool<>(new Pool.PoolObject<Rect>() {            @Override            public Rect get() { return new Rect();}        });    }    @Override    public RecyclerView.LayoutParams generateDefaultLayoutParams() {        return new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,                ViewGroup.LayoutParams.WRAP_CONTENT);    }    @Override    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {        if (getItemCount() <= 0 || state.isPreLayout()) { return;}        detachAndScrapAttachedViews(recycler);        updateMeasurements(recycler);        fill(recycler, state);    }    private void fill(RecyclerView.Recycler recycler, RecyclerView.State state) {        if (getItemCount() <= 0 || state.isPreLayout()) { return;}        Rect displayRect = new Rect(0, mVerticalOffset,                getHorizontalSpace(), getVerticalSpace() + mVerticalOffset);        for (int i = 0; i < getItemCount(); i++) {            Rect frame = mItemFrames.get(i);            View view = recycler.getViewForPosition(i);            if (Rect.intersects(displayRect, frame)) {                addView(view);                measureChildWithMargins(view, 0, 0);                layoutDecorated(view, frame.left, frame.top - mVerticalOffset,                        frame.right, frame.bottom - mVerticalOffset);            } else {                removeAndRecycleView(view,recycler);            }        }    }    public boolean canScrollVertically() {        return true;    }    @Override    public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {        detachAndScrapAttachedViews(recycler);        if (mVerticalOffset + dy < 0) {            dy = -mVerticalOffset;        } else if (mVerticalOffset + dy > mTotalHeight - getVerticalSpace()) {            dy = mTotalHeight - getVerticalSpace() - mVerticalOffset;        }        offsetChildrenVertical(-dy);        mVerticalOffset += dy;        fill(recycler, state);        return dy;    }    public void scrollToTop() {        mVerticalOffset = 0;        requestLayout();    }    private int getHorizontalSpace() {        return getWidth() - getPaddingLeft() - getPaddingRight();    }    private int getVerticalSpace() {        return getHeight() - getPaddingTop() - getPaddingBottom();    }    public void updateMeasurements(RecyclerView.Recycler recycler){        mTotalHeight = 0;        mItemFrames.clear();        int width = getHorizontalSpace();        for (int i = 0; i < getItemCount(); i++) {            Rect item = mItemFrames.get(i);            View view = recycler.getViewForPosition(i);            measureChildWithMargins(view, 0, 0);            int itemWidth = getDecoratedMeasuredWidth(view);            int itemHeight = getDecoratedMeasuredHeight(view);            // 每一组的第一行            if (i == 0) {                item.set(0, 0, itemWidth, itemHeight);                mTotalHeight += itemHeight;            } else if (i > 0) {                View preView = recycler.getViewForPosition(i - 1);                measureChildWithMargins(preView, 0, 0);                if (mItemFrames.get(i - 1).right + itemWidth > width) {                    int preItemHeight = getDecoratedMeasuredHeight(preView);                    int top = mItemFrames.get(i - 1).top + preItemHeight;                    item.set(0, top, itemWidth,top + itemHeight);                    mTotalHeight += itemHeight;                } else {                    item.set(mItemFrames.get(i - 1).right, mItemFrames.get(i - 1).top,                            mItemFrames.get(i - 1).right + itemWidth,                            mItemFrames.get(i - 1).top + itemHeight);                }            }        }    }}class Pool<T> {    private SparseArrayCompat<T> mPool;    private PoolObject<T> mPoolObject;    public Pool(PoolObject<T> poolObject) {        mPool = new SparseArrayCompat<>();        mPoolObject = poolObject;    }    public void clear() {        mPool.clear();    }    public T get(int key) {        T res = mPool.get(key);        if (res == null) {            res = mPoolObject.get();            mPool.put(key, res);        }        return res;    }    public interface PoolObject<T> {        T get();    }}