在内容提供者中发通知的代码
ContentResolver cr = getContext().getContentResolver();
//发出通知，所有注册在这个uri上的内容观察者都可以收到通知
cr.notifyChange(uri, null);
1.java
package com.itheima.mycontentprovider;
import com.itheima.mycontentprovider.db.MyOpenHelper;
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;
public class PersonProvider extends ContentProvider {
private SQLiteDatabase db;
//创建uri匹配器
UriMatcher um = new UriMatcher(UriMatcher.NO_MATCH);
{
//添加匹配规则
//arg0:主机名
//arg1:路径
//arg2:匹配码
um.addURI("com.itheima.people", "person", 1);//content://com.itheima.people/person
um.addURI("com.itheima.people", "handsome", 2);//content://com.itheima.people/handsome
um.addURI("com.itheima.people", "person/#", 3);//content://com.itheima.people/person/10
}
//内容提供者创建时调用
@Override
public boolean onCreate() {
MyOpenHelper oh = new MyOpenHelper(getContext());
db = oh.getWritableDatabase();
return false;
}
//values:其他应用要插的数据
@Override
public Uri insert(Uri uri, ContentValues values) {
if(um.match(uri) == 1){
db.insert("person", null, values);
//数据库改变了,内容提供者发出通知
//arg0:通知发到哪个uri上，注册在这个uri上的内容观察者都可以收到通知
getContext().getContentResolver().notifyChange(uri, null);
}
else if(um.match(uri) == 2){
db.insert("handsome", null, values);
getContext().getContentResolver().notifyChange(uri, null);
}
else{
throw new IllegalArgumentException("uri传错啦傻逼");
}
return uri;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
int i = 0;
if(um.match(uri) == 1){
i = db.delete("person", selection, selectionArgs);
}
else if(um.match(uri) == 2){
i = db.delete("handsome", selection, selectionArgs);
}
else{
throw new IllegalArgumentException("uri又传错啦傻逼");
}
return i;
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
int i = db.update("person", values, selection, selectionArgs);
return i;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
Cursor cursor = null;
if(um.match(uri) == 1){
cursor = db.query("person", projection, selection, selectionArgs, null, null, sortOrder, null);
}
else if(um.match(uri) == 2){
cursor = db.query("handsome", projection, selection, selectionArgs, null, null, sortOrder, null);
}
else if(um.match(uri) == 3){
//取出uri末尾携带的数字
long id = ContentUris.parseId(uri);
cursor = db.query("person", projection, "_id = ?", new String[]{"" + id}, null, null, sortOrder, null);
}
return cursor;
}
//返回通过指定uri获取的数据的mimetype
@Override
public String getType(Uri uri) {
if(um.match(uri) == 1){
return "vnd.android.cursor.dir/person";
}
else if(um.match(uri) == 2){
return "vnd.android.cursor.dir/handsome";
}
else if(um.match(uri) == 3){
return "vnd.android.cursor.item/person";
}
return null;
}
}
2.java
package com.itheima.receivenotify;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.database.ContentObserver;
import android.view.Menu;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//注册内容观察者接收01发送的通知
getContentResolver().registerContentObserver(Uri.parse("content://com.itheima.people"),
true, new ContentObserver(new Handler()) {
@Override
public void onChange(boolean selfChange) {
// TODO Auto-generated method stub
super.onChange(selfChange);
System.out.println("01数据库改变");
}
});
}
}
3.java
package com.itheima.other;
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.Menu;
import android.view.View;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void insert(View v){
//通过内容提供者把数据插入01数据库
//1.获取contentResolver
ContentResolver resolver = getContentResolver();
//2.访问内容提供者，插入数据
ContentValues values = new ContentValues();
values.put("name", "流氓润");
values.put("phone", 138992);
values.put("money", 14000);
//arg0:指定内容提供者的主机名
resolver.insert(Uri.parse("content://com.itheima.people/person"), values);
values.clear();
values.put("name", "侃哥");
values.put("phone", 15999);
//arg0:指定内容提供者的主机名
resolver.insert(Uri.parse("content://com.itheima.people/handsome"), values);
}
public void delete(View v){
ContentResolver resolver = getContentResolver();
int i = resolver.delete(Uri.parse("content://com.itheima.people"), "name = ?", new String[]{"凤姐"});
System.out.println(i);
}
public void update(View v){
ContentResolver resolver = getContentResolver();
ContentValues values = new ContentValues();
values.put("money", 16001);
int i = resolver.update(Uri.parse("content://com.itheima.people"), values, "name = ?", new String[]{"春晓"});
System.out.println(i);
}
public void query(View v){
ContentResolver resolver = getContentResolver();
Cursor cursor = resolver.query(Uri.parse("content://com.itheima.people/person"), null, null, null, null);
while(cursor.moveToNext()){
String name = cursor.getString(1);
String phone = cursor.getString(2);
String money = cursor.getString(3);
System.out.println(name + ";" + phone + ";" + money);
}
}
public void queryOne(View v){
ContentResolver resolver = getContentResolver();
Cursor cursor = resolver.query(Uri.parse("content://com.itheima.people/person/4"), null, null, null, null);
if(cursor.moveToNext()){
String name = cursor.getString(1);
String phone = cursor.getString(2);
String money = cursor.getString(3);
System.out.println(name + ";" + phone + ";" + money);
}
}
}
注意：
每当 3.java对数据库进行增删修改操作时，1.java就会发出数据库数据变化的通知给2.java，2.java接收通知打印数据库数据发生来变化的信息