ContentProvider 与Content Resolver

<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"
    >
    <Button 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="query"
        android:text="查询"
        />
    <Button
		android:layout_width="match_parent"
		android:layout_height="wrap_content"
		android:onClick="insert"
		android:text="插入" />
	<Button
		android:layout_width="match_parent"
		android:layout_height="wrap_content"
		android:onClick="update"
		android:text="更新" />
	<Button
		android:layout_width="match_parent"
		android:layout_height="wrap_content"
		android:onClick="delete"
		android:text="删除" />


</LinearLayout>

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MainActivity.java

package com.example.firstresolver;

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

public class MainActivity extends Activity {
	ContentResolver contentResolver;
	Uri uri=Uri.parse("content://com.example.firstprovider/");

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		//获取系统的ContentResolver对象
		contentResolver=getContentResolver();
		
	}
	
	public void query(View source)
	{
		//调用ContentResolver的query方法,实际返回的是该Uri对应的ContentProvider的query()的返回值
		Cursor c=contentResolver.query(uri, null, "query_where", null, null);
		Toast.makeText(this, "远程ContentProvider返回的Cursor为："+c, Toast.LENGTH_SHORT).show();
		
	}
	
	public void insert(View source)
	{
		ContentValues values=new ContentValues();
		values.put("name", "fkjava");
		//调用ContentResolver的insert方法
		Uri newUri=contentResolver.insert(uri, values);
		Toast.makeText(this, "远程ContentProvide新插入记录的Uri为："+newUri, Toast.LENGTH_SHORT).show();
	}
	
	public void update(View source)
	{
		ContentValues values = new ContentValues();
		values.put("name", "fkjava");
		// 调用ContentResolver的update()方法。
		// 实际返回的是该Uri对应的ContentProvider的update()的返回值
		int count = contentResolver.update(uri, values
			, "update_where", null);
		Toast.makeText(this, "远程ContentProvide更新记录数为："
			+ count, Toast.LENGTH_LONG).show();
	}

	public void delete(View source)
	{
		// 调用ContentResolver的delete()方法。
		// 实际返回的是该Uri对应的ContentProvider的delete()的返回值
		int count = contentResolver.delete(uri
			, "delete_where", null);
		Toast.makeText(this, "远程ContentProvide删除记录数为："
			+ count, Toast.LENGTH_LONG).show();
	}

}

------------------------------

FirstProvider.java

package com.example.firstprovider;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;

public class FirstProvider extends ContentProvider {
	public FirstProvider() {
	}
	@Override
	public boolean onCreate() {
		// TODO: Implement this to initialize your content provider on startup.
		System.out.println("----conCreate方法被调用----");
		return true;
	}
	@Override
	public String getType(Uri uri) {
		// TODO: Implement this to handle requests for the MIME type of the data
		// at the given URI.
		//throw new UnsupportedOperationException("Not yet implemented");
		return null;
	}

	@Override
	public int delete(Uri uri, String selection, String[] selectionArgs) {
		// Implement this to handle requests to delete one or more rows.
		//throw new UnsupportedOperationException("Not yet implemented");
		System.out.println(uri+"----delete方法被调用----");
		System.out.println("selection参数为: "+selection);
		return 0;
	}



	@Override
	public Uri insert(Uri uri, ContentValues values) {
		// TODO: Implement this to handle requests to insert a new row.
		//throw new UnsupportedOperationException("Not yet implemented");
		System.out.println(uri+"----insert方法被调用----");
		System.out.println("valuse参数为: "+values);
		return null;
	}



	@Override
	public Cursor query(Uri uri, String[] projection, String selection,
			String[] selectionArgs, String sortOrder) {
		// TODO: Implement this to handle query requests from clients.
		System.out.println(uri+"----query方法被调用----");
		System.out.println("selection参数为:"+selection);
		//throw new UnsupportedOperationException("Not yet implemented");
		return null;
	}

	@Override
	public int update(Uri uri, ContentValues values, String selection,
			String[] selectionArgs) {
		// TODO: Implement this to handle requests to update one or more rows.
		//throw new UnsupportedOperationException("Not yet implemented");
		System.out.println(uri+"----update方法被调用----");
		System.out.println("selection参数为: "+selection+", values参数为："+values);
		return 0;
	}
}