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); }}
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) { } });
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); }}
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
<?xml version="1.0" encoding="utf-8"?><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
<?xml version="1.0" encoding="utf-8"?><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
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