Android RecycleView高度自适应

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Android RecycleView高度自适应

高度自适应

当RecycleView的高度为wrap_content 并且item的高度也是wrap_content时 RecycleView的高度就不会根据内容自动设置

解决方法如下

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import android.content.Context;
import android.graphics.Rect;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;

public class MyLinearLayoutManager extends LinearLayoutManager {

    public MyLinearLayoutManager(Context context) {
        super(context);
    }

    public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
    }

    public MyLinearLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }


    @Override
    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
        super.onLayoutChildren(recycler, state);
        // 先把所有的View先从RecyclerView中detach掉，然后标记为"Scrap"状态，表示这些View处于可被重用状态(非显示中)。
        // 实际就是把View放到了Recycler中的一个集合中。
        detachAndScrapAttachedViews(recycler);
        calculateChildrenSite(recycler);
    }

    int totalHeight = 0;

    private void calculateChildrenSite(RecyclerView.Recycler recycler) {
        totalHeight = 0;
        for (int i = 0; i < getItemCount(); i++) {
            // 遍历Recycler中保存的View取出来
            View view = recycler.getViewForPosition(i);
            addView(view); // 因为刚刚进行了detach操作，所以现在可以重新添加
            measureChildWithMargins(view, 0, 0); // 通知测量view的margin值
            int width = getDecoratedMeasuredWidth(view); // 计算view实际大小，包括了ItemDecorator中设置的偏移量。
            int height = getDecoratedMeasuredHeight(view);

            Rect mTmpRect = new Rect();
            //调用这个方法能够调整ItemView的大小，以除去ItemDecorator。
            calculateItemDecorationsForChild(view, mTmpRect);

            // 调用这句我们指定了该View的显示区域，并将View显示上去，此时所有区域都用于显示View，
            //包括ItemDecorator设置的距离。
            layoutDecorated(view, 0, totalHeight, width, totalHeight + height);
            totalHeight += height;
        }
    }

}

RecycleView

添加引用

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implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:3.0.4'

数据适配器Adapter

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class BookAdapter(data: MutableList<CollBookBean>) :
    BaseQuickAdapter<CollBookBean, BaseViewHolder>(R.layout.s_book_item, data) {

    override fun convert(helper: BaseViewHolder, item: CollBookBean) {
        var top_image_view = helper.getView<ImageView>(R.id.top_image_view)
        helper.setText(R.id.name_tv, item.title)
        var cover = item.cover
        if (cover != null) {
            cover = BaseConfig.showImageUrl + cover
            GlideUtil.loadAllImage(mContext,5,cover, top_image_view)
        } else {
            GlideUtil.loadImage(mContext, R.mipmap.read_no_cover, top_image_view)
        }
    }
}

页面

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private fun initRefreshView() {
  m_refreshlayoyt.setOnRefreshLoadMoreListener(object : OnRefreshLoadMoreListener {
    override fun onLoadMore(refreshLayout: RefreshLayout) {
      loadmore(rorder)
    }

    override fun onRefresh(refreshLayout: RefreshLayout) {
      refresh(rorder)
    }
  })
}

private fun initRecycleView() {
  mListAdapter = BookAdapter(mDatas)
  recycleview?.adapter = mListAdapter

  recycleview?.layoutManager = GridLayoutManager(mContext, 6)

  recycleview?.addItemDecoration(
    RecycleViewDivider(
      mContext,
      LinearLayoutManager.VERTICAL,
      1,
      ZJColor.line
    )
  )

  // 设置item动画
  recycleview?.itemAnimator = DefaultItemAnimator()
  mListAdapter?.setOnItemClickListener { 
    adapter, view, position ->
    onItemClick(view, position)
  }

  mListAdapter?.animationEnable = true
  recycleview?.adapter = mListAdapter
  mListAdapter?.setEmptyView(R.layout.empty_bg)
}

分割线

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import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.view.View;

import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

public class RecycleViewDivider extends RecyclerView.ItemDecoration {

    private Paint mPaint;
    private Drawable mDivider;
    private int mDividerHeight = 1;//分割线高度，默认为1px
    private int mOrientation;//列表的方向：LinearLayoutManager.VERTICAL或LinearLayoutManager.HORIZONTAL
    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
    private boolean isShowLast = true;//是否显示最后的线

    /**
     * 默认分割线：高度为2px，颜色为灰色
     *
     * @param context
     * @param orientation 列表方向
     */
    public RecycleViewDivider(Context context, int orientation) {
        if (orientation != LinearLayoutManager.VERTICAL && orientation != LinearLayoutManager.HORIZONTAL) {
            throw new IllegalArgumentException("请输入正确的参数！");
        }
        mOrientation = orientation;

        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    public RecycleViewDivider(Context context, int orientation, boolean isShowLast) {
        this.isShowLast = isShowLast;
        if (orientation != LinearLayoutManager.VERTICAL && orientation != LinearLayoutManager.HORIZONTAL) {
            throw new IllegalArgumentException("请输入正确的参数！");
        }
        mOrientation = orientation;

        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    /**
     * 自定义分割线
     *
     * @param context
     * @param orientation 列表方向
     * @param drawableId  分割线图片
     */
    public RecycleViewDivider(Context context, int orientation, int drawableId) {
        this(context, orientation);
        mDivider = ContextCompat.getDrawable(context, drawableId);
        mDividerHeight = mDivider.getIntrinsicHeight();
        if (mDividerHeight == 0) {
            mDividerHeight = 1;
        }
    }

    /**
     * 自定义分割线
     *
     * @param context
     * @param orientation   列表方向
     * @param dividerHeight 分割线高度
     * @param dividerColor  分割线颜色
     */
    public RecycleViewDivider(Context context, int orientation, int dividerHeight, int dividerColor) {
        this(context, orientation);
        mDividerHeight = dividerHeight;
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(dividerColor);
        mPaint.setStyle(Paint.Style.FILL);
    }

    /**
     * 自定义分割线
     *
     * @param context
     * @param orientation   列表方向
     * @param dividerHeight 分割线高度
     * @param dividerColor  分割线颜色
     */
    public RecycleViewDivider(Context context, int orientation, int dividerHeight, int dividerColor,boolean isShowLast) {
        this(context, orientation,isShowLast);
        mDividerHeight = dividerHeight;
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(dividerColor);
        mPaint.setStyle(Paint.Style.FILL);
    }


    //获取分割线尺寸
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        outRect.set(0, 0, 0, mDividerHeight);
    }

    //绘制分割线
    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        super.onDraw(c, parent, state);
        if (mOrientation == LinearLayoutManager.HORIZONTAL) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }
    }

    //绘制横向 ques_item 分割线
    private void drawHorizontal(Canvas canvas, RecyclerView parent) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getMeasuredWidth() - parent.getPaddingRight();
        final int childSize = parent.getChildCount();
        int dividerCount = childSize;
        if (!isShowLast) {
            dividerCount = childSize - 1;
        }
        for (int i = 0; i < dividerCount; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            final int top = child.getBottom() + layoutParams.bottomMargin;
            final int bottom = top + mDividerHeight;
            if (mDivider != null) {
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(canvas);
            }
            if (mPaint != null) {
                canvas.drawRect(left, top, right, bottom, mPaint);
            }
        }
    }

    //绘制纵向 ques_item 分割线
    private void drawVertical(Canvas canvas, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getMeasuredHeight() - parent.getPaddingBottom();
        final int childSize = parent.getChildCount();
        int dividerCount = childSize;
        if (!isShowLast) {
            dividerCount = childSize - 1;
        }
        for (int i = 0; i < dividerCount; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            final int left = child.getRight() + layoutParams.rightMargin;
            final int right = left + mDividerHeight;
            if (mDivider != null) {
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(canvas);
            }
            if (mPaint != null) {
                canvas.drawRect(left, top, right, bottom, mPaint);
            }
        }
    }
}

全局上下文

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import android.app.Application;
import android.content.Context;

public class MyApp extends Application {
    private static Context context;

    @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();
    }

    /**
     * 获取全局上下文
     */
    public static Context getContext() {
        return context;
    }
}

添加在manifest中

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<application
    android:name="MyApp" >

然后使用只要需要context但又获取不得或获取麻烦的话，只要使用：

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MyApp.getContext()

注意

最好是在不得已的情况下使用上述方法来获取context，而不是只要用到context就使用MyApplication.getContext()，因为这涉及到View等存在生命周期的问题。