http://blog.csdn.net/carson_ho/article/details/53366570
前言
- 今天我将手把手教大家如何实现具备历史搜索记录的搜索框
目录
1. 使用场景
在敲下代码前,理解用户的功能使用场景是非常重要的,这样有助于我们更好地去进行功能的实现,使用场景如下:
- 用户需要进行某类事物的搜索(通过文字输入进行精确搜索)
- 在搜索框输入时,通过显示搜索历史从而降低用户二次搜索的成本
简单来说,就是输入过字段会保存,当用户再次搜索该字段时,能快速帮助用户输入
2. 功能业务流程
3. 明确功能点
- 功能1:关键字搜索
- 功能2:实时显示历史搜索记录
- 功能3:历史搜索记录保存
- 功能4:将软键盘上的”回车按钮“改为”搜索按钮“
4. 涉及到的知识点
4.1 SQLite数据库的增删改查操作
- 在数据库建立一个叫records的表用于存储搜索历史记录
里面只有一列name来存储历史记录
db.execSQL("create table records(id integer primary key autoincrement,name varchar(200))");
- 通过插入和删除操作数据库里面的数据
- 通过查询操作来显示数据库里面的数据到ListView上
已搜索的关键字再次搜索不重复添加到数据库
注:对于SQLlite数据库的操作详情请看我写的文章: Android:SQLlite数据库操作最详细解析
public class Search_Listview extends ListView {
public Search_Listview(Context context) {
super(context);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
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4.3 监听软键盘回车按钮设置为搜索按钮
给搜索框EditText添加一个OnKeyListener监听器,重写里面的回车键,实现按下回车键搜索。
et_search.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_DOWN) {
写入搜索操作和数据库插入搜索记录操作
}
});
4.4 使用TextWatcher实时筛选
给搜索框EditText添加一个TextWatcher来检测EditText里面的每个字符变化,根据变化之后的内容查询数据库得到结果。
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) {
}
});
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5. 实例Demo
接下来,我将给出详细代码手把手教你实现具备历史搜索记录的搜索框
先下载Demo再进行阅读效果会更好:Carson的Search_Layout_Demo地址
5.1 目录结构
5.2 具体实现如下:
MainActivity.java
package scut.carson_ho.search_layout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
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RccordSQLiteOpenHelper.java
- 作用:继承自SQLiteOpenHelper数据库类的子类,用于创建、管理数据库和版本控制
- 具体代码如下:
对于SQLlite数据库的操作详情请看我写的文章:Android:SQLlite数据库操作最详细解析
package scut.carson_ho.search_layout;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
/**
* Created by Carson_Ho on 16/11/15.
*/
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) {
}
}
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Search_ListView.java
- 作用:用于解决ListView和ScrollView的嵌套冲突
- 具体代码如下:
package scut.carson_ho.search_layout;
import android.content.Context;
import android.util.AttributeSet;
import android.widget.ListView;
/**
* Created by Carson_Ho on 16/11/15.
*/
public class Search_Listview extends ListView {
public Search_Listview(Context context) {
super(context);
}
public Search_Listview(Context context, AttributeSet attrs) {
super(context, attrs);
}
public Search_Listview(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);
}
}
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Search_View.java
- 作用:用于封装搜索框功能的所有操作(涵盖历史搜索记录的插入、删除、查询和显示)
- 具体代码如下:
package scut.carson_ho.search_layout;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.Toast;
/**
* Created by Carson_Ho on 16/11/15.
*/
public class Search_View extends LinearLayout {
private Context context;
private TextView tv_clear;
private EditText et_search;
private TextView tv_tip;
private ImageView iv_search;
private Search_Listview listView;
private BaseAdapter adapter;
private RecordSQLiteOpenHelper helper ;
private SQLiteDatabase db;
public Search_View(Context context) {
super(context);
this.context = context;
init();
}
public Search_View(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
init();
}
public Search_View(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.context = context;
init();
}
private void init(){
initView();
helper = new RecordSQLiteOpenHelper(context);
queryData("");
tv_clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
deleteData();
queryData("");
}
});
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();
queryData(tempName);
}
});
et_search.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_DOWN) {
boolean hasData = hasData(et_search.getText().toString().trim());
if (!hasData) {
insertData(et_search.getText().toString().trim());
queryData("");
}
Toast.makeText(context, "点击搜索", Toast.LENGTH_SHORT).show();
}
return false;
}
});
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(context, name, Toast.LENGTH_SHORT).show();
}
});
iv_search.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
boolean hasData = hasData(et_search.getText().toString().trim());
if (!hasData) {
insertData(et_search.getText().toString().trim());
queryData("");
}
Toast.makeText(context, "clicked!", Toast.LENGTH_SHORT).show();
}
});
}
/**
* 封装的函数
*/
private void initView(){
LayoutInflater.from(context).inflate(R.layout.search_layout,this);
et_search = (EditText) findViewById(R.id.et_search);
tv_clear = (TextView) findViewById(R.id.tv_clear);
tv_tip = (TextView) findViewById(R.id.tv_tip);
listView = (Search_Listview) findViewById(R.id.listView);
iv_search = (ImageView) findViewById(R.id.iv_search);
}
private void insertData(String tempName) {
db = helper.getWritableDatabase();
db.execSQL("insert into records(name) values('" + tempName + "')");
db.close();
}
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);
adapter = new SimpleCursorAdapter(context, android.R.layout.simple_list_item_1, cursor, new String[] { "name" },
new int[] { android.R.id.text1 }, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
listView.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
private boolean hasData(String tempName) {
Cursor cursor = helper.getReadableDatabase().rawQuery(
"select id as _id,name from records where name =?", new String[]{tempName});
return cursor.moveToNext();
}
private void deleteData() {
db = helper.getWritableDatabase();
db.execSQL("delete from records");
db.close();
}
}
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search_layout.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusableInTouchMode="true"
android:orientation="vertical">
<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="fill_parent"
android:layout_weight="264"
android:background="@null"
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" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/search"
android:layout_gravity="center_vertical"
android:id="@+id/iv_search"/>
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"/>
<scut.carson_ho.search_layout.Search_Listview
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="wrap_content">
scut.carson_ho.search_layout.Search_Listview>
LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#EEEEEE"/>
<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"/>
LinearLayout>
ScrollView>
LinearLayout>
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activity_main.xml
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="scut.carson_ho.search_layout.MainActivity">
<scut.carson_ho.search_layout.Search_View
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/search_layout"/>
RelativeLayout>
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5.3 测试结果
5.4 Demo地址
Carson的Github地址:Search_Layout_Demo
6. 总结
- 通过阅读本文,你已经全面了解Android中如何实现具备历史搜索记录的搜索框
- 接下来会介绍继续介绍Android开发中的常用知识,有兴趣可以继续关注Carson_Ho的安卓开发笔记