目录
设计目标
学习安卓四大组件之一的contentprovider，请使用其方法类进行数据获取。
创建两个APP，自建一个provider，然后在另一个app中使用resolver调用这个provider，让两个APP之间实现连接功能
功能说明
点击MyResolver 中的按钮，对MyContentProvider中数据库中的表进行相应的操作
核心代码
MyResolver
MyResolver的MainActivity
对另一个app的表进行处理
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;
public class MainActivity extends AppCompatActivity {
private Button button;
private ContentResolver resolver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button=findViewById(R.id.button);
Uri uri=Uri.parse("content://xr.provider1/student");
ContentResolver resolver=getContentResolver();
ContentValues values=new ContentValues();
values.put("name","zhangsan");
values.put("age",20);
Integer.parseInt("20");
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
resolver.insert(uri,values);
}
});
}
}
MyResolver下xml设计
加入一个按钮
<?xml version="1.0" encoding="utf-8"?>
<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="这是resolver"
android:textSize="35sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/button"
android:layout_width="157dp"
android:layout_height="74dp"
android:text="Receieve"
android:textSize="25sp"
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="0.224" />
</androidx.constraintlayout.widget.ConstraintLayout>
MyContentProvider中的代码
类似于上一次数据库实验的相关操作
MyDAO.java
package com.example.mycontentprovider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.net.Uri;
import android.util.Log;
public class MyDAO {
private SQLiteDatabase database;
private SQLiteOpenHelper myopenhelper;
private Context context;
private Uri uri=Uri.parse("content://xr.provider1");
public MyDAO(Context context){
this.context=context;
myopenhelper=new MyDBhelper(context,"xrDB",null,1);
database=myopenhelper.getReadableDatabase();
database.execSQL("drop table if exists student");
database.execSQL("create table student(id integer primary key autoincrement,"+" name varchar, age integer)");
}
public Uri addvalue(Uri uri, ContentValues values){
long rowID=database.insert("student",null,values);
if(rowID == -1){
Log.d("DAO","数据插入失败");
return null;
}
else {
Uri insertUri= ContentUris.withAppendedId(uri,rowID);
Log.d("xr","ContentUris:"+insertUri.toString());
context.getContentResolver().notifyChange(insertUri,null);
return insertUri;
}
}
}
MyDBhelper.java
package com.example.mycontentprovider;
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, name, 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 sqLiteDatabase, int i, int i1) {
}
}
MyContentProvider.java
package com.example.mycontentprovider;
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.addvalue(uri,values);
}
@Override
public boolean onCreate() {
Context context=getContext();
myDAO=new MyDAO(context);
return true;
}
@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");
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MyDAO myDAO=new MyDAO(this);
}
}
结果截图
同时点击两个运行键
点击按钮
打开数据库，运算结果如下
; 实验小结
本次实验中我学习了安卓四大组件之一的contentprovider，并使用了其数据获取的相关方法，根据参考文档，将两个APP连接起来，在一个APP中进行按钮点击，另一个APP中对数据库进行实际操作并得到结果，这次实验之后，要加强对app连接的理解，多加练习，将其运用到其他课程的学习中去
仓库地址
Original: https://blog.csdn.net/Fan12191118/article/details/128024801
Author: Fan12191118
Title: 安卓作业三
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