赵雅智_ProviderContent监听数据变化

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当程序A在执行insert、update、delete时，通过getContext().getContentResolver().notifyChange(uri, observer)方法来告诉所有注册在该Uri的监听者数据发生改变

参数1uri：注册的uri

参数2observer：注册的监听者

/** * 插入操作 */@Overridepublic Uri insert(Uri uri, ContentValues values) {if (uriMatcher.match(uri) != USERSCODE) {throw new IllegalArgumentException("unknow URI" + uri);}SQLiteDatabase db = dh.getReadableDatabase();long rowId = db.insert("users", "username", values);//监听数据变化，通知注册在uri上的监听者//参数1：注册的uri，参数2：监听者getContext().getContentResolver().notifyChange(uri, null);return ContentUris.withAppendedId(uri, rowId);}

在B程序通过registerContentObserver(Uri uri, boolean notifyForDescendents, ContentObserver observer)方法来监听A程序的数据改变

参数1：uri
- 匹配的uri
参数2：notifyForDescendents
- content://www.csdn.com.provider.userContentProvider/users
- true:模糊匹配content://www.csdn.com.provider.userContentProvider
- false:绝对匹配content://www.csdn.com.provider.userContentProvider/users
参数3：observer
- observer为监听实例，需要通过继承ContentObserver类，并重写onChange(booleab selfChange)方法，该方法在监听Uri的ContentProvider的数据发生改变时触发该方法

package com.example.android_providers;import android.app.Activity;import android.content.ContentResolver;import android.database.ContentObserver;import android.database.Cursor;import android.net.Uri;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.support.v4.widget.SimpleCursorAdapter;import android.view.View;import android.widget.ListView;import android.widget.TextView;public class CopyOfMainActivity extends Activity {private ListView lv_users;private TextView tv_tip;private SimpleCursorAdapter adapter;private ContentResolver contentResolver;private static final String URL = "content://www.csdn.com.provider.userContentProvider/users";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);lv_users = (ListView) findViewById(R.id.lv_users);tv_tip = (TextView) findViewById(R.id.tv_tip);// 获取内容解析器对象contentResolver = getContentResolver();initDate();// 注册监听器getContentResolver().registerContentObserver(Uri.parse(URL), true,new UserContentObserver(handler));}/* * 初始化数据 */private void initDate() {// 执行查询Cursor c = contentResolver.query(Uri.parse(URL), new String[] {"userid as _id", "username", "userphone" }, null, null,"userid desc");// 控制层adapter = new SimpleCursorAdapter(this, R.layout.item_phone, c,new String[] { "username", "userphone" }, new int[] {R.id.tv_name, R.id.tv_phone },SimpleCursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);lv_users.setAdapter(adapter);}class UserContentObserver extends ContentObserver {private Handler handler;public UserContentObserver(Handler handler) {super(handler);this.handler = handler;}@Overridepublic void onChange(boolean selfChange) {super.onChange(selfChange);tv_tip.setVisibility(View.VISIBLE);tv_tip.setText("有新的信息，请点击加载");}}private Handler handler = new Handler() {@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);}};}

实例应用：

http://blog.csdn.net/zhaoyazhi2129/article/details/30064965

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