【安卓實驗】實驗六、contentprovider實驗+SQLite資料庫的實作-有解無憂

【實驗名稱】實驗六、contentprovider實驗+SQLite資料庫的實作
【實驗目的】
1、掌握如何在Android 開發中使用 SQLite 資料庫
2、熟悉設計資料庫表結構的方法與步驟
3、理解contentprovider的使用方法及流程，理解ContentProvider、Resolver、Uri、Urimatcher等的原理，
【實驗內容】
1、實作contentprovider和contentresolver通過uri的呼叫；
2、實作contentprovider對資料庫sqlite的功能：增、刪、改、查；
3、資料庫的表結構自行設計；

【實驗要求】
1、配置SQLite 資料庫的運行環境
2、熟悉contentprovider對資料庫sqlite增、刪、改、查的具體操作和流程
3、充分理解SQLite資料庫的使用原理和方式

（請完成如下部分）

訪問通訊錄

在這里插入圖片描述

資料庫的增刪改查

在這里插入圖片描述

代碼

MainActivity.java

package com.example.test05_contentprovider;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

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

    }

    public void toOne(View view){
        Intent intent = new Intent(MainActivity.this, ContentActivity.class);
        startActivity(intent);
    }

    public void toTwo(View view){
        Intent intent = new Intent(MainActivity.this, SQLActivity.class);
        startActivity(intent);
    }

}

ContentActivity.java

package com.example.test05_contentprovider;

import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.widget.TextView;

import androidx.annotation.Nullable;

public class ContentActivity extends Activity {
    //希望獲得通訊錄中的姓名
    private String columns = ContactsContract.Contacts.DISPLAY_NAME;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.contentlayout);
        TextView textView = (TextView) findViewById(R.id.callName);
        textView.setText(getQueryData());
    }

    private CharSequence getQueryData(){
        //用于保存獲取的聯系人
        StringBuilder stringBuilder = new StringBuilder();
        ContentResolver resolver = getContentResolver();
        Cursor cursor = resolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                null,null,null,null);
        //獲得姓名記錄的索引值
        int displayNameIndex = cursor.getColumnIndex(columns);
        for(cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()){
            String displayName = cursor.getString(displayNameIndex);
            stringBuilder.append(displayName+"\n");
            System.out.println(stringBuilder);
        }
        cursor.close();
        return stringBuilder.toString();
    }
}

PersonDBOpenHelper.java

package com.example.test05_contentprovider;

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

public class PersonDBOpenHelper extends SQLiteOpenHelper {
    //構造方法
    public PersonDBOpenHelper(Context context) {
        super(context,"person.db",null,1);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table info(_id integer primary key autoincrement,name varchar(20))");
    }

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

    }

}

PersonProvider.java

package com.example.test05_contentprovider;

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

public class PersonProvider extends ContentProvider {
    //定義一個URI路徑的匹配器  匹配失敗回傳-1
    private static UriMatcher mUriMatcher = new UriMatcher(-1);
    //匹配成功
    private static final int SUCCESS = 1;
    //資料庫操作類的物件
    private PersonDBOpenHelper helper;
    //添加路徑匹配器的規則
    static {
        mUriMatcher.addURI("cn.itcast.contentobserverdb","info",SUCCESS);
    }
    @Override
    public boolean onCreate() {
        helper = new PersonDBOpenHelper(getContext());
        return false;
    }

    @Nullable
    @Override
    public Cursor query(@NonNull Uri uri, @Nullable String[] strings, @Nullable String s, @Nullable String[] strings1, @Nullable String s1) {
        int code = mUriMatcher.match(uri);
        if(code == SUCCESS){
            SQLiteDatabase db = helper.getReadableDatabase();
            return db.query("info",strings,s,strings1,null,null,s1);
        }else{
            try {
                throw new IllegalAccessException("路徑不正確，不會給你提供資料");
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }

        return null;
    }

    @Nullable
    @Override
    public String getType(@NonNull Uri uri) {
        return null;
    }

    @Nullable
    @Override
    public Uri insert(@NonNull Uri uri, @Nullable ContentValues values) {
        int code = mUriMatcher.match(uri);
        if(code == SUCCESS){
            SQLiteDatabase db = helper.getReadableDatabase();
            long rowId = db.insert("info",null,values);
            if(rowId>0){
                Uri insertedUri = ContentUris.withAppendedId(uri, rowId);
                //提示資料庫的內容變化了
                getContext().getContentResolver().notifyChange(insertedUri,null);
                return insertedUri;
            }
            db.close();
            return uri;
        }else{
            try {
                throw new IllegalAccessException("路徑不正確，不會插入資料");
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    public int delete(@NonNull Uri uri, @Nullable String s, @Nullable String[] strings) {
        int code = mUriMatcher.match(uri);
        if(code == SUCCESS){
            SQLiteDatabase db = helper.getReadableDatabase();
            int count = db.delete("info",s,strings);
            if(count>0){
                getContext().getContentResolver().notifyChange(uri,null);
            }
            db.close();
            return count;
        }else{
            try {
                throw new IllegalAccessException("路徑不正確，不會洗掉資料");
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
        return code;
    }

    @Override
    public int update(@NonNull Uri uri, @Nullable ContentValues contentValues, @Nullable String s, @Nullable String[] strings) {

        int code = mUriMatcher.match(uri);
        if(code == SUCCESS){
            SQLiteDatabase db = helper.getReadableDatabase();
            int count = db.update("info",contentValues,s,strings);
            if(count>0){
                getContext().getContentResolver().notifyChange(uri,null);
            }
            db.close();
            return count;
        }else{
            try {
                throw new IllegalAccessException("路徑不正確，不能更新資料");
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }return 0;
    }
}

SQLActivity.java

package com.example.test05_contentprovider;

import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import androidx.annotation.Nullable;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

public class SQLActivity extends Activity {
    private ContentResolver resolver;
    private Uri uri;
    private ContentValues values;
    private Button btnInsert;
    private Button btnUpdate;
    private Button btnDelete;
    private Button btnSelect;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sqllayout);
        createDB();
        createDB();
    }

    private void createDB(){
        //創建資料庫
        PersonDBOpenHelper helper = new PersonDBOpenHelper(this);
        SQLiteDatabase db = helper.getWritableDatabase();
        for (int i = 0; i< 3;i++){
            ContentValues values = new ContentValues();
            values.put("name","peach"+i);
            db.insert("info",null,values);
        }
        System.out.println("創建成功");
        db.close();
    }

    public void btnAdd(View view){
        System.out.println("????????????????????");
        resolver = getContentResolver();
        uri = Uri.parse("content://cn.itcast.contentobserverdb/info");
        values = new ContentValues();

        Random random = new Random();
        values.put("name","add_itcast"+random.nextInt(10));
        Uri newUri = resolver.insert(uri,values);
        Toast.makeText(this,"成功添加",Toast.LENGTH_SHORT).show();
        Log.i("資料庫","add");
    }

    public void btnQuery(View view){
        System.out.println("????????????????????");
        resolver = getContentResolver();
        uri = Uri.parse("content://cn.itcast.contentobserverdb/info");
        values = new ContentValues();

        List<Map<String,String>> data = new ArrayList<Map<String ,String >>();
        Cursor cursor = resolver.query(uri, new String[]{"_id","name"},null,null,null);
        while(cursor.moveToNext()){
            Map<String,String> map = new HashMap<String,String>();
            map.put("_id",cursor.getString(0));
            map.put("name",cursor.getString(1));
            data.add(map);
        }
        cursor.close();
        Log.i("ahadhsahf","safk"+data.toString());
    }

    public void btnUpdate(View view){
        System.out.println("--------更新！！！");
        resolver = getContentResolver();
        uri = Uri.parse("content://cn.itcast.contentobserverdb/info");
        values = new ContentValues();

        values.put("name","hhhhhhh");
        int updateCount = resolver.update(uri,values,"name=?",new String[]{"peach0"});
        Toast.makeText(this,"成功更新了"+updateCount+"行",Toast.LENGTH_SHORT).show();

    }

    public void btnDelete(View view){
        System.out.println("????????????????????");
        resolver = getContentResolver();
        uri = Uri.parse("content://cn.itcast.contentobserverdb/info");
        values = new ContentValues();

        int deleteCount = resolver.delete(uri,"name=?",new String[]{"peach0"});
        resolver.delete(uri,"name=?",new String[]{"peach1"});
        resolver.delete(uri,"name=?",new String[]{"hhhhhhh"});
        Toast.makeText(this,"成功洗掉了"+deleteCount+"行",Toast.LENGTH_SHORT).show();
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/toOne"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="訪問通訊錄"
        android:onClick="toOne"
        />
    <Button
        android:id="@+id/toTwo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="資料庫"
        android:onClick="toTwo"
        />
</LinearLayout>

contentlayout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ContentActivity">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="讀取到的聯系人姓名："
        android:textSize="30dp"/>

    <TextView
        android:id="@+id/callName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20dp"
     />

</LinearLayout>

sqllayout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".SQLActivity">

   <Button
       android:id="@+id/add"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:onClick="btnAdd"
       android:text="增加"/>

    <Button
        android:id="@+id/update"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="btnUpdate"
        android:text="更新"/>

    <Button
        android:id="@+id/delete"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="btnDelete"
        android:text="洗掉"/>

    <Button
        android:id="@+id/query"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="btnQuery"
        android:text="查詢"/>

</LinearLayout>

【實驗分析或心得】
掌握如何在Android 開發中使用 SQLite 資料庫,熟悉設計資料庫表結構的方法與步驟并且理解contentprovider的使用方法及流程，理解ContentProvider、Resolver、Uri、Urimatcher等的原理，識訓頗多，

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