移动开发课程——作业3

2023年11月11日下午9:39 • 大数据 • 阅读 45

作业要求：

1、contentprovider是安卓四大组件之一，请使用其方法类进行数据获取；

2、请自建一个provider，然后在另一个app中使用resolver调用这个provider。

3、本次作业请启用新项目，理论上需要两个APP进行实验。

作业代码：

1.contentprovider项目代码MyDBHelper.java

package com.example.contentprovider;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

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);
        Log.d("zyj", "MyDBHelper is running...");
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        sqLiteDatabase.execSQL("create table student(id integer primary key autoincrement, name varchar,age integer)");
        Log.d("zyj", "DBonCreate is running...");

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

2.MyDao.java

package com.example.contentprovider;

import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;

public class MyDAO {

    private final Context context;
    private  SQLiteDatabase database;

    public MyDAO(Context context) {
        this.context = context;
        MyDBHelper dbHelper = new MyDBHelper(context,"zyjDB",null,1);
        database =dbHelper.getWritableDatabase();

    }

    public Uri DAOinsert(ContentValues values){
        long rowid = database.insert("student",null,values);

        Uri uri = Uri.parse("content://zyj.ContentProvider/student");

        Uri inserturi= ContentUris.withAppendedId(uri,rowid);

        context.getContentResolver().notifyChange(inserturi,null);
        return inserturi;

    }

}

3.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" package="com.example.contentprovider">

    <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.ContentProvider" tools:targetapi="31">
        <provider android:name=".MyContentProvider" android:authorities="zyj.ContentProvider" android:enabled="true" android:exported="true"></provider>
        <activity android:name=".MainActivity" android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN">

                <category android:name="android.intent.category.LAUNCHER">
            </category></action></intent-filter>
        </activity>
    </application>

</manifest>

4.Contentresolver项目代码

package com.example.contentresolver;

import androidx.appcompat.app.AppCompatActivity;

import android.content.ContentResolver;
import android.content.ContentValues;
import android.net.Uri;
import android.os.Bundle;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ContentResolver resolver = getContentResolver();
        ContentValues values = new ContentValues();
        values.put("name", "zyj");
        values.put("age", "19");
        Uri uri = Uri.parse("content://zyj.ContentProvider/student");
        Button button = findViewById(R.id.button);
        button.setOnClickListener(v -> {
            resolver.insert(uri, values);

        });
    }
}

结果截图：