android contentprovider内容提供者

contentprovider内容提供者：让其他app可以访问私有数据库（文件）

1.AndroidManifest.xml

配置provider

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

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >

　　　　<!--android:name="com.example.dbtest.PersonContentProvider"  必须为内容提供者类的路径 不然会报notfoundclass-->
<provider
android:name="com.example.dbtest.PersonContentProvider"
android:authorities="com.example.dbtest.provider.personprovider"
android:exported="true"></provider>

<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

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

</manifest>

2.PersonContentProvider

package com.example.dbtest;

import com.example.dbtest.dbHelper.DbOpenHelper;

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

public class PersonContentProvider extends ContentProvider {

private DbOpenHelper helper;
//定义一个uri的匹配器用于匹配uri 如果路径不满足条件 返回-1
private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);

private static final int INSERT = 1;
private static final int DELETE = 2;
private static final int UPDATE = 3;
private static final int QUERY = 4;

static{
matcher.addURI("com.example.dbtest.provider.personprovider", "insert", INSERT);
matcher.addURI("com.example.dbtest.provider.personprovider", "delete", DELETE);
matcher.addURI("com.example.dbtest.provider.personprovider", "update", UPDATE);
matcher.addURI("com.example.dbtest.provider.personprovider", "query", QUERY);
}

//content://com.itheima.db.personprovider/insert 添加操作
//content://com.itheima.db.personprovider/delete 删除操作
//content://com.itheima.db.personprovider/update 更新操作
//content://com.itheima.db.personprovider/query  查询操作

@Override
public boolean onCreate() {
helper = new DbOpenHelper(getContext());
return true;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
if(matcher.match(uri)==QUERY)
{
SQLiteDatabase db = helper.getWritableDatabase();
Cursor cursor = db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
//注意  使用contentprovider时  不要将数据关闭掉   不然拿不到数据
//db.close(); 不要关闭
return cursor;
}
else
{
throw new IllegalArgumentException("路径不配对，不能执行查询操作");
}
}

@Override
public String getType(Uri uri) {

return null;
}

@Override
public Uri insert(Uri uri, ContentValues values) {
if(matcher.match(uri)==INSERT)
{
SQLiteDatabase db = helper.getWritableDatabase();
db.insert("person",null,values);
}
else
{
throw new IllegalArgumentException("路径不配对，不能执行插入操作");
}
return null;
}

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
if(matcher.match(uri)==DELETE)
{
SQLiteDatabase db = helper.getWritableDatabase();
db.delete("person", selection, selectionArgs);
}
else
{
throw new IllegalArgumentException("路径不配对，不能执行删除操作");
}
return 0;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
if(matcher.match(uri)==UPDATE)
{
SQLiteDatabase db = helper.getWritableDatabase();
db.update("person", values, selection, selectionArgs);
}
else
{
throw new IllegalArgumentException("路径不配对，不能执行修改操作");
}
return 0;
}

}

3.其他app调用内容提供者

package com.example.getcontentprovider;

import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

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

public void query(View view)
{
System.out.println("start query...............");
ContentResolver resolver = getContentResolver();
Uri uri = Uri.parse("content://com.example.dbtest.provider.personprovider/query");
Cursor cursor = resolver.query(uri, null, null, null, null);

StringBuffer sb = new StringBuffer();
while(cursor.moveToNext())
{
System.out.println("name:"+cursor.getString(cursor.getColumnIndex("name")));
sb.append("name:"+cursor.getString(cursor.getColumnIndex("name"))+"\n");

}
System.out.println("end query..............");

Toast.makeText(this, sb.toString(),0).show();

}

public void delete(View view)
{
ContentResolver resolver = getContentResolver();
Uri uri = Uri.parse("content://com.example.dbtest.provider.personprovider/delete");
resolver.delete(uri, "id=?", new String[]{"1"});

Toast.makeText(this, "删除成功",0).show();

}

public void update(View view)
{
ContentResolver resolver = getContentResolver();
Uri uri = Uri.parse("content://com.example.dbtest.provider.personprovider/update");
ContentValues values = new ContentValues();
values.put("name", "张三");
resolver.update(uri, values, "id=?", new String[]{"1"});

Toast.makeText(this, "修改成功",0).show();

}

public void insert(View view)
{

ContentResolver resolver = getContentResolver();
Uri uri = Uri.parse("content://com.example.dbtest.provider.personprovider/insert");
ContentValues values = new ContentValues();
values.put("name", "李四");
resolver.insert(uri, values);

Toast.makeText(this, "修改成功",0).show();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}