实验六:基于SQLite的通讯录
一、 实验目的
- 掌握SQLiteOpenHelper类结构
- 掌握基于SQLite数据库的应用开发过程
- 掌握Content Provider发布数据的方法
- 掌握Content Resolver获取数据的方法
二、 实验内容
简要介绍本次实验的内容及要求。(通过文字与图片说明)
实现基于SQLite数据库的通信录应用,运行结果如图1-图3所示:通过单击增加图标打开添加通信录界面,通过单击通信录中的各条信息可删除选中项。
三、 理论
Android系统中集成了SQLite 数据库,并且为数据库的操作提供了相关的类和方法,便于没
有数据库开发经验的开发者编写程序。另外,Android平台中利用Content Provider 机制来实现跨应用程序数据共享。一个应用程序可以通过Content Provider 来发布自己的数据,其他的应用程序可以通过Content Resolver来获取共享数据。
四、 设计步骤
将设计内容细化为具体步骤,完善每步的具体内容。
- 建立数据库操作类DatabaseHelper,代码如下所示。
- 修改主布局如下,请将下列空出代码部分补全。
- 修改主Activity文件MainActivity.java,代码如下所示。
- 创建列表视图布局文件relationlist.xml,请将下列空出代码部分补全。
- 创建添加联系人界面布局文件addrelation,请将下列空出代码部分补全。
- 创建增加联系人界面主Activity文件AddRelationActivity.java,代码如下所示。
- 在AndroidManifest.xml文件中添加AddRelationActivity界面应用。
五、 效果图展示
根据实验内容的要求,把设计的每部分效果图进行展示,并对核心代码进行分析。(此处需要截图)
六、 实验总结
此处是对本次实验过程的总结(主要学习到了哪些知识,有什么心得体会等)。
九、 注意事项
下拉框需要设置一个values的资源,就像是本题中的groups
时间紧迫,有错的或者不懂的联系我吧。溜了溜了~~~
八、 代码
DatabaseHelper.java
package com.example.test4;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import androidx.annotation.Nullable;
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "MyRelation.db";
private static final String TABLE_NAME = "relation";
private static final String CREATE_TABLE = "create table relation(_id integer primary key autoincrement,name text,tel text,groupName text);";
private SQLiteDatabase db;
DatabaseHelper(Context context) {
super(context, DB_NAME, null, 2);
}
public void insert(ContentValues values) {
SQLiteDatabase db = getWritableDatabase();
db.insert(TABLE_NAME, null, values);
db.close();
}
public void del(int id) {
if(db==null) db=getWritableDatabase();
db.delete(TABLE_NAME, "_id = ?", new String[]{ String.valueOf(id) });
}
public Cursor query() {
SQLiteDatabase db = getWritableDatabase();
Cursor cursor = db.query(TABLE_NAME, null, null, null, null, null, null);
return cursor;
}
public DatabaseHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
}
public void close() {
if(db!=null) db.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
this.db = db;
db.execSQL(CREATE_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { }
}
MainActivity.java
package com.example.test4;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.SimpleCursorAdapter;
public class MainActivity extends AppCompatActivity {
private ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView);
getRelationFromDB();
}
private void getRelationFromDB() {
final DatabaseHelper databaseHelper = new DatabaseHelper(this);
Cursor cursor = databaseHelper.query();
String[] from = {"_id", "name", "tel", "groupName"};
int[] to = {R.id._id, R.id.name, R.id.tel, R.id.group};
SimpleCursorAdapter simpleCursorAdapter = new SimpleCursorAdapter(this, R.layout.relationlist, cursor, from, to);
listView.setAdapter(simpleCursorAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
final long temp = id;
//Log.d("temp", "onItemClick");
AlertDialog.Builder adBuilder = new AlertDialog.Builder(MainActivity.this);
adBuilder.setMessage("确定要删除记录吗?").setPositiveButton("确认", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
databaseHelper.del((int)temp);
Cursor cursor = databaseHelper.query();
String[] from = {"_id", "name", "tel", "groupName"};
int[] to = {R.id._id, R.id.name, R.id.tel, R.id.group};
SimpleCursorAdapter simpleCursorAdapter = new SimpleCursorAdapter(getApplicationContext(), R.layout.relationlist, cursor, from, to);
MainActivity.this.listView.setAdapter(simpleCursorAdapter);
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) { }
});
AlertDialog alertDialog = adBuilder.create();
alertDialog.show();
}
});
databaseHelper.close();
}
public void add(View view) {
Intent intent = new Intent(MainActivity.this, AddRelationActivity.class);
startActivityForResult(intent, 0x111);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode==0x111&&resultCode==0x111) getRelationFromDB();
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
android:background="#fffae4"
tools:context=".MainActivity">
<TextView
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:background="#FFE4E1"
android:text="通讯录"
android:textSize="40dp"
/>
<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/title"
/>
<ImageView
android:src="@drawable/add"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:onClick="add"
/>
</RelativeLayout>
AddRelationActivity.java
package com.example.test4;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
public class AddRelationActivity extends AppCompatActivity {
private EditText addName, addTel;
private Spinner addGroup;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.addrelation);
addName = (EditText) findViewById(R.id.addName);
addTel = (EditText) findViewById(R.id.addTel);
addGroup = (Spinner) findViewById(R.id.addGroup);
}
public void save(View view) {
final ContentValues values = new ContentValues();
values.put("name", addName.getText().toString());
values.put("tel", addTel.getText().toString());
values.put("groupName", addGroup.getSelectedItem().toString());
//Toast.makeText(this, values.toString(), Toast.LENGTH_SHORT).show();
final DatabaseHelper databaseHelper = new DatabaseHelper(getApplicationContext());
final AlertDialog.Builder adBuilder = new AlertDialog.Builder(this);
adBuilder.setMessage("确认保存记录吗?").setPositiveButton("确认",new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
databaseHelper.insert(values);
Intent intent = getIntent();
setResult(0x111, intent);
AddRelationActivity.this.finish();
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) { }
});
AlertDialog alertDialog = adBuilder.create();
alertDialog.show();
}
}
addrelation.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical"
android:background="#fffae4"
tools:context=".AddRelationActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="姓名"
android:textSize="30dp"
/>
<EditText
android:id="@+id/addName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="30dp"
android:hint="请输入姓名"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="电话"
android:textSize="30dp"
/>
<EditText
android:id="@+id/addTel"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="30dp"
android:hint="请输入电话号码"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="所属组"
android:textSize="30dp"
/>
<Spinner
android:id="@+id/addGroup"
android:layout_width="match_parent"
android:layout_height="30dp"
android:entries="@array/groups"
/>
<Button
android:id="@+id/save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:onClick="save"
android:text="保存"
/>
</LinearLayout>
relationlist.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:descendantFocusability="blocksDescendants"
android:orientation="horizontal"
android:background="#fffae4">
<TextView
android:id="@+id/_id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="id"
android:textSize="20dp"
android:visibility="gone"
/>
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="40dp"
android:text="name"
android:textSize="20dp"
android:layout_weight="1"
/>
<TextView
android:id="@+id/tel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="tel"
android:textSize="20dp"
android:layout_weight="3"
/>
<TextView
android:id="@+id/group"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="40dp"
android:text="group"
android:textSize="20dp"
android:layout_weight="1"
/>
<CheckBox
android:id="@+id/select"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:clickable="false"
android:visibility="gone"
/>
</LinearLayout>
groups.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="groups">
<item>同事</item>
<item>同学</item>
<item>朋友</item>
</string-array>
</resources>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<application
android:allowBackup="true"
android:dataExtractionRules="@xml/data_extraction_rules"
android:fullBackupContent="@xml/backup_rules"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.Test4"
tools:targetApi="31">
<activity
android:name=".AddRelationActivity"
android:exported="false">
<meta-data
android:name="android.app.lib_name"
android:value="" />
</activity>
<activity
android:name=".MainActivity"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<meta-data
android:name="android.app.lib_name"
android:value="" />
</activity>
</application>
</manifest>