Android 自訂ContentProvider和ContentObserver的完整使用

標籤：contentobserver

在自訂ContentProvider結合ContentObserver一起使用時，自己寫的ContentProvider,在執行完insert、delete和update後，要手動地調用getContentResolver().notifyChange()這個方法來通知改動的產生。

直接上代碼：

MainActivity

<span style="font-family:SimSun;font-size:14px;"><span style="font-family:SimSun;font-size:14px;">package com.jackie.contentobserver;import java.util.ArrayList;import android.net.Uri;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.app.Activity;import android.app.AlertDialog;import android.app.AlertDialog.Builder;import android.content.ContentResolver;import android.content.ContentUris;import android.content.ContentValues;import android.database.Cursor;import android.util.Log;import android.view.LayoutInflater;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ListView;import android.widget.TextView;public class MainActivity extends Activity {private ArrayList<Person> mList;private ListView mListView;private ContentResolver resolver;private MyBaseAdapter mBaseAdapter;private Handler mHandler;private AdapterContentObserver mAdapterContentObserver;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mListView = (ListView) findViewById(R.id.lv_person);initData();mBaseAdapter = new MyBaseAdapter(this, mList);mListView.setAdapter(mBaseAdapter);mHandler = new Handler();mAdapterContentObserver = new AdapterContentObserver(this, mHandler);resolver.registerContentObserver(Uri.parse("content://com.jackie.provider.person/person"), true, mAdapterContentObserver);//註冊簡訊變化監聽//this.getContentResolver().registerContentObserver(Uri.parse("content://sms/"), true, content)}@Overrideprotected void onDestroy() {resolver.unregisterContentObserver(mAdapterContentObserver);super.onDestroy();}private ArrayList<Person> initData() {mList = new ArrayList<Person>();resolver = getContentResolver();Cursor cursor = resolver.query(Uri.parse("content://com.jackie.provider.person/person"), null, null, null, null);while (cursor.moveToNext()) {Person person = new Person();person.set_id(cursor.getInt(cursor.getColumnIndex("_id")));person.setName(cursor.getString(cursor.getColumnIndex("name")));mList.add(person);}return mList;}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.activity_main, menu);return true;}@Overridepublic boolean onMenuItemSelected(int featureId, MenuItem item) {switch (item.getItemId()) {case R.id.menu_settings://AlertDialog.Builder builder = new AlertDialog.Builder(this);//builder.setTitle("提示").setMessage("您確定要退出?");//builder.create().show();ContentValues values = new ContentValues();values.put("name", "Jackie");Uri mUri = resolver.insert(Uri.parse("content://com.jackie.provider.person/person"), values);//方法一： 重新查詢資料庫即時重新整理//        mBaseAdapter = new MyBaseAdapter(this, initData());//        mListView.setAdapter(mBaseAdapter);//方法二： 當adapter綁定的list變化時，調用adapter的notifyDataSetChanged方法即時重新整理（不用重複查詢資料庫，效率更高）//long id = ContentUris.parseId(mUri);//mList.add(new Person(id, "chengjie"));//mBaseAdapter.notifyDataSetChanged();//方法三： 內容觀察者ContentObserver<span style="color:#ff0000;">//自己寫的ContentProvider,在執行完insert、delete和update後，要手動地調用getContentResolver().notifyChange()這個方法來通知改動的產生(請參考MyProvider.java的方法)</span>break;default:break;}return super.onMenuItemSelected(featureId, item);}}</span></span>

AdapterContentObserver.java

<span style="font-family:SimSun;font-size:14px;"><span style="font-family:SimSun;font-size:14px;">package com.jackie.contentobserver;import android.content.ContentResolver;import android.content.Context;import android.database.ContentObserver;import android.database.Cursor;import android.net.Uri;import android.os.Handler;import android.util.Log;import android.widget.Toast;public class AdapterContentObserver extends ContentObserver {private Context context;private Handler handler;private static final int PERSON_UPDATE = 0;public AdapterContentObserver(Handler handler) {super(handler);// TODO Auto-generated constructor stub}public AdapterContentObserver(Context context, Handler handler) {super(handler);this.context = context;this.handler = handler;}//當監聽的Uri發生變化，便會執行這個方法@Overridepublic void onChange(boolean selfChange, Uri uri) {super.onChange(selfChange, uri);        ContentResolver resolver = context.getContentResolver();        // 擷取最新的一條資料        Cursor cursor = resolver.query(uri, null, null, null, "_id desc limit 1");        while (cursor.moveToNext()) {            int _id = cursor.getInt(cursor.getColumnIndex("_id"));            Toast.makeText(context, "資料庫更新了, _id 為： " + _id, Toast.LENGTH_SHORT).show();        }        cursor.close();}}</span></span>

DBHelper.java

<span style="font-family:SimSun;font-size:14px;"><span style="font-family:SimSun;font-size:14px;">package com.jackie.contentobserver;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class DBHelper extends SQLiteOpenHelper {public DBHelper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);// TODO Auto-generated constructor stub}@Overridepublic void onCreate(SQLiteDatabase db) {db.execSQL("create table if not exists person(_id integer primary key autoincrement, name text)");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}}</span></span>

MyBaseAdapter.java

<span style="font-family:SimSun;font-size:14px;"><span style="font-family:SimSun;font-size:14px;">package com.jackie.contentobserver;import java.util.ArrayList;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.TextView;public class MyBaseAdapter extends BaseAdapter {private ViewHolder holder;private Context context;private ArrayList<Person> mList;public MyBaseAdapter(Context context, ArrayList<Person> mList) {this.context = context;this.mList = mList;}@Overridepublic int getCount() {return mList.size();}@Overridepublic Object getItem(int position) {return mList.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {LayoutInflater mInflater = LayoutInflater.from(context);if (convertView == null) {holder = new ViewHolder();convertView = mInflater.inflate(R.layout.listview_item, null);holder.idTexitView = (TextView) convertView.findViewById(R.id.tv_id);holder.nameTextView = (TextView) convertView.findViewById(R.id.tv_name);convertView.setTag(holder);} else {holder = (ViewHolder) convertView.getTag();}holder.idTexitView.setText(mList.get(position).get_id() + "");holder.nameTextView.setText(mList.get(position).getName());return convertView;}class ViewHolder {TextView idTexitView;TextView nameTextView;}}</span></span>

MyProvider.java

<span style="font-family:SimSun;font-size:14px;"><span style="font-family:SimSun;font-size:14px;">package com.jackie.contentobserver;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 MyProvider extends ContentProvider {private final static String AUTHORITH = "com.jackie.provider.person";private final static String PERSONS_PATH = "person";private final static String PERSON_PATH = "person/#";private final static int PERSON = 1;private final static int PERSONS = 2;private final static String DATABASE_NAME = "person_db";private final static String TABLE_NAME = "person";private final static String TABLE_COLUMN_ID = "_id";private final static String TABLE_COLUMN_NAME = "name";private final static UriMatcher mUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);static {mUriMatcher.addURI(AUTHORITH, PERSONS_PATH, PERSONS);mUriMatcher.addURI(AUTHORITH, PERSON_PATH, PERSON);}private DBHelper helper = null;@Overridepublic boolean onCreate() {helper  = new DBHelper(getContext(), DATABASE_NAME, null, 1);return true;}@Overridepublic Cursor query(Uri uri, String[] projection, String selection,String[] selectionArgs, String sortOrder) {SQLiteDatabase database = helper.getWritableDatabase();switch (mUriMatcher.match(uri)) {case PERSON:long id = ContentUris.parseId(uri);String where = TABLE_COLUMN_ID + "=" + id;if (selection != null && !"".equals(selection)) {selection = where + "and" + selection;}return database.query(TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);case PERSONS:return database.query(TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);default:throw new IllegalArgumentException("UnKnown uri: " + uri);}}@Overridepublic String getType(Uri uri) {switch (mUriMatcher.match(uri)) {case PERSON:return "vnd.android.cursor.item";case PERSONS:return "vnd.android.cursor.dir";default:throw new IllegalArgumentException("UnKnown uri: " + uri);}}@Overridepublic Uri insert(Uri uri, ContentValues values) {SQLiteDatabase database = helper.getWritableDatabase();long id = database.insert(TABLE_NAME, TABLE_COLUMN_NAME, values);<span style="color:#ff0000;">//向外界通知該ContentProvider裡的資料發生了變化 ,以便ContentObserver作出相應getContext().getContentResolver().notifyChange(uri, null);</span>return ContentUris.withAppendedId(uri, id);}@Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {SQLiteDatabase database = helper.getWritableDatabase();switch (mUriMatcher.match(uri)) {case PERSON:long id = ContentUris.parseId(uri);String where = TABLE_COLUMN_ID + "=" + id;if (selection != null && !"".equals(selection)) {selection = where + "and" + selection;}return database.delete(TABLE_NAME, selection, selectionArgs);case PERSONS:return database.delete(TABLE_NAME, selection, selectionArgs);default:throw new IllegalArgumentException("UnKnown uri: " + uri);}}@Overridepublic int update(Uri uri, ContentValues values, String selection,String[] selectionArgs) {// TODO Auto-generated method stubreturn 0;}}</span></span>

Person.java

<span style="font-family:SimSun;font-size:14px;"><span style="font-family:SimSun;font-size:14px;">package com.jackie.contentobserver;public class Person {private long _id;private String name;public Person(long _id, String name) {super();this._id = _id;this.name = name;}public Person() {super();// TODO Auto-generated constructor stub}public long get_id() {return _id;}public void set_id(long _id) {this._id = _id;}public String getName() {return name;}public void setName(String name) {this.name = name;}}</span></span>

Android 自訂ContentProvider和ContentObserver的完整使用