RecyclerView wrap_content

RecyclerView 内容包裹 根据其内容而填充大小，网上各种奇葩方案 要么重写layoutManager 反复测量child 要么丢失divider 要么性能低下

在这里给出google 官方的解决方案 是在support lib>23.2.0

compile 'com.android.support:recyclerview-v7:23.2.0'

最关键的一句:

   RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setAutoMeasureEnabled(true);
源码:

  * @param enabled <code>True</code> if the Layout should be measured by the
         *                             RecyclerView, <code>false</code> if the LayoutManager wants
         *                             to measure itself.
         *
         * @see #setMeasuredDimension(Rect, int, int)
         * @see #isAutoMeasureEnabled()
         */
        public void setAutoMeasureEnabled(boolean enabled) {
            mAutoMeasure = enabled;
        }

例子:

activity_test.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#6cf">

    </android.support.v7.widget.RecyclerView>

</LinearLayout>
activity

package gitosctest.gitosc_studyproject;

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

/**
 * @author xuanyouwu
 * @email [email protected]
 * @time 2016-03-24 12:30
 */
public class TestActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.rv);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setAutoMeasureEnabled(true);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(new MyAdapter());
    }

    class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyHolder> {

        class MyHolder extends RecyclerView.ViewHolder {

            TextView textView;

            public MyHolder(View itemView) {
                super(itemView);
                textView = (TextView) itemView.findViewById(R.id.textView);
            }
        }


        @Override
        public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_string, parent, false);
            return new MyHolder(v);
        }

        @Override
        public void onBindViewHolder(MyHolder holder, int position) {
            holder.textView.setText("item:" + position);
        }

        @Override
        public int getItemCount() {
            return 3;
        }
    }
}


效果图:

当recyclerView 嵌套在scrollView 中依旧可以展现出wrap_content

如: