搜索框(searchView)使用

    <SearchView
        android:id="@+id/searchview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="100dp" />

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <SearchView
        android:id="@+id/searchview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="100dp" />

    <ListView
        android:id="@+id/listview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent">

    </ListView>

</android.support.constraint.ConstraintLayout>

package com.example.user.searchview;

import android.os.Trace;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SearchView;

public class MainActivity extends AppCompatActivity {

    ListView lv;
    SearchView sv;

    String[] name= {"111",  "222", "333"};

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

        lv = (ListView)findViewById(R.id.listview);

        lv.setAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, name));

        lv.setTextFilterEnabled(true);

        sv = (SearchView)findViewById(R.id.searchview);

        //是否自动缩小为图标
        sv.setIconifiedByDefault(false);
        //现实默认文字
        sv.setQueryHint("查找");

        sv.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {

                if(!TextUtils.isEmpty(newText)){
                    lv.setFilterText(newText);
                }else{
                    lv.clearTextFilter();
                }

                return true;
            }
        });


    }
}