文章目录
设计目标：
- contentprovider是安卓四大组件之一，请使用其方法类进行数据获取；
- 请自建一个provider，然后在另一个app中使用resolver调用这个provider；
- 请使用两个APP进行实验。
功能说明：
- 在Myresolver项目中实现对Myprovider项目的数据库的修改
代码解析：
Myprovider项目：
MyContentProvider.java:
package com.example.myprovider;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
public class MyContentProvider extends ContentProvider {
private MyDAO myDAO;
public MyContentProvider() {
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
throw new UnsupportedOperationException("Not yet implemented");
}
@Override
public String getType(Uri uri) {
throw new UnsupportedOperationException("Not yet implemented");
}
@Override
public Uri insert(Uri uri, ContentValues values) {
return myDAO.plfInsert(values);
}
@Override
public boolean onCreate() {
Context context = getContext();
myDAO = new MyDAO(context);
return false;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
throw new UnsupportedOperationException("Not yet implemented");
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
throw new UnsupportedOperationException("Not yet implemented");
}
}
MyDAO.java:
package com.example.myprovider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
public class MyDAO<database> {
private Context context;
private SQLiteDatabase database;
public MyDAO(Context context)
{
this.context=context;
MyDBHelper myDBHelper=new MyDBHelper(context,"plfDB",null,1);
database=myDBHelper.getWritableDatabase();
}
public Uri plfInsert(ContentValues values){
Uri uri=Uri.parse("content://plf/.provider1");
long rowId=database.insert("student",null,values);
Uri inserturi = ContentUris.withAppendedId(uri,rowId);
context.getContentResolver().notifyChange(inserturi,null);
return inserturi;
}
}
MyDBHelper.java:
package com.example.myprovider;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import androidx.annotation.Nullable;
public class MyDBHelper extends SQLiteOpenHelper {
public MyDBHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
super(context, "plfDB", factory, version);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("create table student (id integer primary key autoincrement,name varchar(20),age integer)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
AndroidManifest.xml
在AndroidManifest.xml文件中添加如下代码：
<provider
android:name=".MyContentProvider"
android:authorities="plf.provider1"
android:enabled="true"
android:exported="true">provider>
Myresolver项目：
MainActivity.java:
package com.example.myresolver;
import androidx.appcompat.app.AppCompatActivity;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button=findViewById(R.id.button);
TextView textView=findViewById(R.id.textView);
ContentResolver contentResolver=getContentResolver();
Uri uri=Uri.parse("content://plf.provider1/student");
ContentValues contentValues=new ContentValues();
contentValues.put("name","plf");
contentValues.put("age",21);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
contentResolver.insert(uri,contentValues);
}
});
}
}
activity_main.xml:
<androidx.constraintlayout.widget.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">
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="resolver"
android:textSize="48sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.475"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.483" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView"
app:layout_constraintVertical_bias="0.168" />
androidx.constraintlayout.widget.ConstraintLayout>
页面设计：
AndroidManifest.xml
在AndroidManifest.xml文件中添加如下代码：
<queries>
<package android:name="com.example.myprovider">package>
queries>
运行展示截图：
在点击Myresolver项目的button时，在Myprovider项目的数据库中会添加一组数据：
; 源码仓库地址：
Original: https://blog.csdn.net/qq_57000518/article/details/128008065
Author: qq_57000518
Title: contentprovider的使用
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