Android搜索功能的案例，本地保存搜索历史记录

同事负责开发的APP有一个搜索功能，并且需要显示搜索的历史记录，我闲暇之余帮她开发了这个功能，现把该页面抽取成一个demo分享给大家。

实现效果如图所示：

本案例实现起来很简单，所以可以直接拿来嵌入项目中使用，涉及到的知识点：
- 数据库的增删改查操作
- ListView和ScrollView的嵌套冲突解决
- 监听软键盘回车按钮设置为搜索按钮
- 使用TextWatcher( )实时筛选
- 已搜索的关键字再次搜索不重复添加到数据库
- 刚进入页面设置软键盘不因为EditText而自动弹出

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代码

1. RecordSQLiteOpenHelper.java

package com.cwvs.microlife;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class RecordSQLiteOpenHelper extends SQLiteOpenHelper {

    private static String name = "temp.db";
    private static Integer version = 1;

    public RecordSQLiteOpenHelper(Context context) {
        super(context, name, null, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table records(id integer primary key autoincrement,name varchar(200))");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }


}

1. MainActivity.java

package com.cwvs.microlife;

import java.util.Date;

import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.KeyEvent;
import android.view.View;
import android.view.Window;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private EditText et_search;
    private TextView tv_tip;
    private MyListView listView;
    private TextView tv_clear;
    private RecordSQLiteOpenHelper helper = new RecordSQLiteOpenHelper(this);;
    private SQLiteDatabase db;
    private BaseAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        // 初始化控件
        initView();

        // 清空搜索历史
        tv_clear.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                deleteData();
                queryData("");
            }
        });

        // 搜索框的键盘搜索键点击回调
        et_search.setOnKeyListener(new View.OnKeyListener() {// 输入完后按键盘上的搜索键

            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if (keyCode == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_DOWN) {// 修改回车键功能
                    // 先隐藏键盘
                    ((InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(
                            getCurrentFocus().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
                    // 按完搜索键后将当前查询的关键字保存起来,如果该关键字已经存在就不执行保存
                    boolean hasData = hasData(et_search.getText().toString().trim());
                    if (!hasData) {
                        insertData(et_search.getText().toString().trim());
                        queryData("");
                    }
                    // TODO 根据输入的内容模糊查询商品，并跳转到另一个界面，由你自己去实现
                    Toast.makeText(MainActivity.this, "clicked!", Toast.LENGTH_SHORT).show();

                }
                return false;
            }
        });

        // 搜索框的文本变化实时监听
        et_search.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                if (s.toString().trim().length() == 0) {
                    tv_tip.setText("搜索历史");
                } else {
                    tv_tip.setText("搜索结果");
                }
                String tempName = et_search.getText().toString();
                // 根据tempName去模糊查询数据库中有没有数据
                queryData(tempName);

            }
        });

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView parent, View view, int position, long id) {
                TextView textView = (TextView) view.findViewById(android.R.id.text1);
                String name = textView.getText().toString();
                et_search.setText(name);
                Toast.makeText(MainActivity.this, name, Toast.LENGTH_SHORT).show();
                // TODO 获取到item上面的文字，根据该关键字跳转到另一个页面查询，由你自己去实现
            }
        });

        // 插入数据，便于测试，否则第一次进入没有数据怎么测试呀？
        Date date = new Date();
        long time = date.getTime();
        insertData("Leo" + time);

        // 第一次进入查询所有的历史记录
        queryData("");
    }

    /**
     * 插入数据
     */
    private void insertData(String tempName) {
        db = helper.getWritableDatabase();
        db.execSQL("insert into records(name) values('" + tempName + "')");
        db.close();
    }

    /**
     * 模糊查询数据
     */
    private void queryData(String tempName) {
        Cursor cursor = helper.getReadableDatabase().rawQuery(
                "select id as _id,name from records where name like '%" + tempName + "%' order by id desc ", null);
        // 创建adapter适配器对象
        adapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor, new String[] { "name" },
                new int[] { android.R.id.text1 }, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
        // 设置适配器
        listView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }
    /**
     * 检查数据库中是否已经有该条记录
     */
    private boolean hasData(String tempName) {
        Cursor cursor = helper.getReadableDatabase().rawQuery(
                "select id as _id,name from records where name =?", new String[]{tempName});
        //判断是否有下一个
        return cursor.moveToNext();
    }

    /**
     * 清空数据
     */
    private void deleteData() {
        db = helper.getWritableDatabase();
        db.execSQL("delete from records");
        db.close();
    }

    private void initView() {
        et_search = (EditText) findViewById(R.id.et_search);
        tv_tip = (TextView) findViewById(R.id.tv_tip);
        listView = (com.cwvs.microlife.MyListView) findViewById(R.id.listView);
        tv_clear = (TextView) findViewById(R.id.tv_clear);

        // 调整EditText左边的搜索按钮的大小
        Drawable drawable = getResources().getDrawable(R.drawable.search);
        drawable.setBounds(0, 0, 60, 60);// 第一0是距左边距离，第二0是距上边距离，60分别是长宽
        et_search.setCompoundDrawables(drawable, null, null, null);// 只放左边
    }
}

1. MyListView.java

package com.cwvs.microlife;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ListView;

public class MyListView extends ListView {
    public MyListView(Context context) {
        super(context);
    }

    public MyListView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
                MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, expandSpec);
    }

}

1. activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:focusableInTouchMode="true"
    android:orientation="vertical"
    tools:context="${relativePackage}.${activityClass}">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:background="#E54141"
        android:orientation="horizontal"
        android:paddingRight="16dp">

        <ImageView
            android:layout_width="45dp"
            android:layout_height="45dp"
            android:layout_gravity="center_vertical"
            android:padding="10dp"
            android:src="@drawable/back" />

        <EditText
            android:id="@+id/et_search"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="@null"
            android:drawableLeft="@drawable/search"
            android:drawablePadding="8dp"
            android:gravity="start|center_vertical"
            android:hint="输入查询的关键字"
            android:imeOptions="actionSearch"
            android:singleLine="true"
            android:textColor="@android:color/white"
            android:textSize="16sp" />

    LinearLayout>


    <ScrollView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                android:paddingLeft="20dp"

                >

                <TextView
                    android:id="@+id/tv_tip"
                    android:layout_width="match_parent"
                    android:layout_height="50dp"
                    android:gravity="left|center_vertical"
                    android:text="搜索历史" />

                <View
                    android:layout_width="match_parent"
                    android:layout_height="1dp"
                    android:background="#EEEEEE">View>

                <com.cwvs.microlife.MyListView
                    android:id="@+id/listView"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">com.cwvs.microlife.MyListView>


            LinearLayout>

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#EEEEEE">View>

            <TextView
                android:id="@+id/tv_clear"
                android:layout_width="match_parent"
                android:layout_height="40dp"
                android:background="#F6F6F6"
                android:gravity="center"
                android:text="清除搜索历史" />

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginBottom="20dp"
                android:background="#EEEEEE">View>
        LinearLayout>

    ScrollView>
LinearLayout>

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完整案例源代码