ContentProvider与ContentResolver实例

1，创建ContentProvider对象，该方法需要继承ContentProvider

FirstContentProvider.java

package com.example.firstcontentprovider;

import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.database.Cursor;
import android.view.Menu;

public class FirstContentProvider extends ContentProvider {

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
System.out.println("delete方法被调用");
System.out.println("where参数为"+selection);
return 0;
}

@Override
public String getType(Uri uri) {
// TODO Auto-generated method stub
return null;
}


@Override
public Uri insert(Uri uri, ContentValues values) {
System.out.println("insert方法被调用");
System.out.println("参数为"+values);
return null;
}

@Override
public boolean onCreate() {
System.out.println("OnCreate方法被调用");
return true;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
System.out.println("query方法被调用");
System.out.println("where参数为"+selection);
return null;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
System.out.println("OnCreate方法被调用");
System.out.println("where参数为"+selection);
return 0;
}
}

配置AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.firstcontentprovider"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.firstcontentprovider.FirstResolver"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />


                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        
        <provider android:name="com.example.firstcontentprovider.FirstContentProvider"
            android:authorities="com.example.firstcontentprovider.firstprovider"
            android:exported="true"/>
        
    </application>
</manifest>

2,创建ContentResolver应用程序

FirstResolver.java

package com.example.firstcontentprovider;


import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;


public class FirstResolver extends Activity{


ContentResolver resolver;
Uri uri=Uri.parse("content://com.example.firstcontentprovider.firstprovider/");


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

//获取系统ContentResolver对象
resolver=getContentResolver();

Button add=(Button) super.findViewById(R.id.add);
Button delete=(Button) super.findViewById(R.id.delete);
Button update=(Button) super.findViewById(R.id.update);
Button query=(Button) super.findViewById(R.id.query);

add.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
insert(arg0);

}
});

delete.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
delete(arg0);

}
});

update.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
update(arg0);

}
});


query.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
query(arg0);

}
});



}


public void delete(View source) {
//返回的是Uri对应的ContentProvider的delete()的返回值
int count=resolver.delete(uri, "delete_where", null);
}




public void insert(View source) {
ContentValues values=new ContentValues();
values.put("name", "hanqing");
Uri returnUri=resolver.insert(uri, values);
}




public void query(View source) {
Cursor c=resolver.query(uri, null, "query_where", null, null);
}


public void update(View source) {
ContentValues values=new ContentValues();
values.put("name", "hanqing");
int count=resolver.update(uri, values, "update_where", null);
}
}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".FirstContentProvider" 
    android:orientation="vertical">


    <Button
        android:id="@+id/add"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="增加" />
    
    
     <Button
        android:id="@+id/delete"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="删除" />
     
     
      <Button
        android:id="@+id/update"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="修改" />
      
       <Button
        android:id="@+id/query"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="查找" />
</LinearLayout>