内容提供者和内容观察者及其应用
内容提供者的实现
1.定义一个类继承ContentProvider类
public class PersonProvider extends ContentProvider {
// 定义一个uri匹配器，用于匹配uri，如果匹配不成功返回-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;
private static final int QUERYONE = 5;
private static final Uri URI = Uri.parse("content://person.db");
private PersonSQLiteOpenHelper helper;
static {
// 添加一组匹配规则
// authority: the authority to match
// path: the path to match. * may be used as a wild card for any text,
// and # may be used as a wild card for numbers.
// code: the code that is returned when a URI is matched against the
// given components. Must be positive.
matcher.addURI("com.itheima.contentprovider.personprovider", "insert",
INSERT);
matcher.addURI("com.itheima.contentprovider.personprovider", "delete",
DELETE);
matcher.addURI("com.itheima.contentprovider.personprovider", "update",
UPDATE);
matcher.addURI("com.itheima.contentprovider.personprovider", "query",
QUERY);
matcher.addURI("com.itheima.contentprovider.personprovider", "query/#",
QUERYONE);
}
@Override
public boolean onCreate() {
this.helper = new PersonSQLiteOpenHelper(getContext());
return false;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
if (matcher.match(uri) == QUERY) {
SQLiteDatabase db = helper.getReadableDatabase();
Cursor cursor = db.query("person", projection, selection,
selectionArgs, null, null, sortOrder);
// 注意这里的db和cursor不能关闭
return cursor;
} else if (matcher.match(uri) == QUERYONE) {
SQLiteDatabase db = helper.getReadableDatabase();
long id = ContentUris.parseId(uri);
Cursor cursor = db.query("person", projection, "id=?",
new String[] { id + "" }, null, null, sortOrder);
// 注意这里的db和cursor不能关闭
return cursor;
} else {
throw new IllegalArgumentException("非法uri");
}
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
if (matcher.match(uri) == DELETE) {
SQLiteDatabase db = helper.getWritableDatabase();
// 注册内容观测者
getContext().getContentResolver().notifyChange(URI, null);
return db.delete("person", selection, selectionArgs);
} else {
throw new IllegalArgumentException("非法uri");
}
}
@Override
public Uri insert(Uri uri, ContentValues values) {
if (matcher.match(uri) == INSERT) {
SQLiteDatabase db = helper.getWritableDatabase();
long id = db.insert("person", null, values);
getContext().getContentResolver().notifyChange(URI, null);
// 返回指定的Uri路劲对象
// content://cn.itcast.provider.custom.usersprovider/users/1
return ContentUris.withAppendedId(uri, id);
} else {
throw new IllegalArgumentException("非法uri");
}
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
if (matcher.match(uri) == UPDATE) {
SQLiteDatabase db = helper.getWritableDatabase();
getContext().getContentResolver().notifyChange(URI, null);
return db.update("person", values, selection, selectionArgs);
} else {
throw new IllegalArgumentException("非法uri");
}
}
/**
* Implement this to handle requests for the MIME type of the data at the
* given URI. The returned MIME type should start with
* vnd.android.cursor.item for a single record, or vnd.android.cursor.dir/
* for multiple items. This method can be called from multiple threads, as
* described in Processes and Threads.
*/
@Override
public String getType(Uri uri) {
if (matcher.match(uri) == QUERY) {
return "vnd.android.cursor.dir/person";
} else if (matcher.match(uri) == QUERYONE) {
return "vnd.android.cursor.item/person";
} else {
return "";
}
}
}
2.定义一个类继承SQLiteOpenHelper类
public class PersonSQLiteOpenHelper extends SQLiteOpenHelper {
private static final String DBFILENAME = "person.db";
private static int db_version = 1;
public PersonSQLiteOpenHelper(Context context) {
super(context, DBFILENAME, null, db_version);
}
/**
* 当数据库第一次创建时调用
*/
@Override
public void onCreate(SQLiteDatabase db) {
String sql = "create table person(id integer primary key autoincrement,name varchar(20),number varchar(20))";
db.execSQL(sql);
}
/**
* 当数据库的版本号发生增加的时候调用
*/
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
System.out.println("数据库更改！");
String sql = "alter table person add account varchar(20)";
db.execSQL(sql);
}
}
3.清单文件中注册内容提供者
<provider
android:name="com.itheima.contentprovider.PersonProvider"
android:authorities="com.itheima.contentprovider.personprovider"
></provider>
第三方软件
public class OtherappActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void getAll(View view) {
ContentResolver resolver = this.getContentResolver();
Uri uri = Uri
.parse("content://com.itheima.contentprovider.personprovider/query");
Cursor cursor = resolver.query(uri, null, null, null, null);
StringBuffer sb = new StringBuffer();
while (cursor.moveToNext()) {
sb.append(cursor.getString(cursor.getColumnIndex("name")) + " -- "
+ cursor.getString(cursor.getColumnIndex("number")));
sb.append("\n");
}
TextView tv_info = (TextView) this.findViewById(R.id.tv_info);
tv_info.setText(sb.toString());
cursor.close();
}
public void getOne(View view) {
ContentResolver resolver = this.getContentResolver();
// Uri uri = Uri
// .parse("content://com.itheima.contentprovider.personprovider/query");
// Cursor cursor = resolver.query(uri, null, "id=?",new String[]{"1"} ,
// null);
Uri uri = Uri
.parse("content://com.itheima.contentprovider.personprovider/query/1");
Cursor cursor = resolver.query(uri, null, null, null, null);
StringBuffer sb = new StringBuffer();
if (cursor.moveToFirst()) {
sb.append(cursor.getString(cursor.getColumnIndex("name")) + " -- "
+ cursor.getString(cursor.getColumnIndex("number")));
sb.append("\n");
}
TextView tv_info = (TextView) this.findViewById(R.id.tv_info);
tv_info.setText(sb.toString());
cursor.close();
}
public void insert(View view) {
ContentResolver resolver = this.getContentResolver();
Uri uri = Uri.parse("content://com.itheima.contentprovider.personprovider/insert");
ContentValues values = new ContentValues();
values.put("name", "reality");
values.put("number", "567");
Uri result = resolver.insert(uri, values);
System.out.println("result = " +result);
}
public void update(View view) {
ContentResolver resolver = this.getContentResolver();
Uri uri = Uri.parse("content://com.itheima.contentprovider.personprovider/update");
ContentValues values = new ContentValues();
values.put("name", "dog");
values.put("number", "110");
int result = resolver.update(uri, values, "id=?", new String[]{"1"});
System.out.println("result = " +result);
}
public void delete(View view) {
ContentResolver resolver = this.getContentResolver();
Uri uri = Uri.parse("content://com.itheima.contentprovider.personprovider/delete");
int result = resolver.delete(uri, "id=?", new String[]{"3"});
System.out.println("result = " + result);
}
}
短信的备份
1.Activity
public class BackupsmsActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void backupSMS(View view) {
Uri uri = Uri.parse("content://sms");
ContentResolver resolver = this.getContentResolver();
Cursor cursor = resolver.query(uri, new String[]{"date","body","address","type"}, null, null, null);
ArrayList<SmsInfo> infos = new ArrayList<SmsInfo>();
while(cursor.moveToNext()){
long date = cursor.getLong(0);
String body = cursor.getString(1);
String address = cursor.getString(2);
int type = cursor.getInt(3);
SmsInfo smsInfo = new SmsInfo(date, body, address, type);
infos.add(smsInfo);
}
SmsUtil.save(this, infos);
}
}
2.工具类
public class SmsUtil {
public static void save(Context context, ArrayList<SmsInfo> infos) {
XmlSerializer xmlSerializer = Xml.newSerializer();
File file = new File(Environment.getExternalStorageDirectory(),
"sms_bak.xml");
try {
FileOutputStream fos = new FileOutputStream(file);
xmlSerializer.setOutput(fos, "utf-8");
xmlSerializer.startDocument("utf-8", true);
xmlSerializer.startTag(null, "smss");
for (SmsInfo info : infos) {
xmlSerializer.startTag(null, "sms");
xmlSerializer.attribute(null, "type", info.getType() + "");
xmlSerializer.startTag(null, "date");
xmlSerializer.text(info.getDate() + "");
xmlSerializer.endTag(null, "date");
xmlSerializer.startTag(null, "address");
xmlSerializer.text(info.getAddress());
xmlSerializer.endTag(null, "address");
xmlSerializer.startTag(null, "body");
xmlSerializer.text(info.getBody());
xmlSerializer.endTag(null, "body");
xmlSerializer.endTag(null, "sms");
}
xmlSerializer.endTag(null, "smss");
xmlSerializer.endDocument();
fos.close();
Toast.makeText(context, "保存成功", 0).show();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(context, "保存失败", 0).show();
}
}
}
3.实体类
public class SmsInfo {
private int id;
private long date;
private String body;
private String address;
private int type;
public SmsInfo() {
super();
// TODO Auto-generated constructor stub
}
public SmsInfo(int id, long date, String body, String address) {
super();
this.id = id;
this.date = date;
this.body = body;
this.address = address;
}
public SmsInfo(long date, String body, String address, int type) {
super();
this.date = date;
this.body = body;
this.address = address;
this.type = type;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public long getDate() {
return date;
}
public void setDate(long date) {
this.date = date;
}
public String getBody() {
return body;
}
public void setBody(String body) {
this.body = body;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
4.授权
<uses-permission android:name="android.permission.WRITE_SMS"/>
<uses-permission android:name="android.permission.READ_SMS"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
插入一条记录到系统短信应用
public class InsertsmsActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new Thread(){
public void run(){
try {
Thread.sleep(10000);
Uri uri = Uri.parse("content://sms");
ContentResolver resolver = getContentResolver();
ContentValues values = new ContentValues();
values.put("address", "10086");
values.put("type", 1);
values.put("date", System.currentTimeMillis());
values.put("body", "您的余额还有100,000,000元！");
resolver.insert(uri, values);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}.start();
}
}
<uses-permission android:name="android.permission.READ_SMS"/>
<uses-permission android:name="android.permission.WRITE_SMS"/>
内容观察者
public class MainActivity extends Activity {
private static final Uri URI= Uri.parse("content://person.db");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ContentResolver resolver = this.getContentResolver();
/**
* If true changes to URIs beginning with uri will also cause notifications to be sent.
* If false only changes to the exact URI specified by uri will cause notifications to be sent.
* If true, than any URI values at or below the specified URI will also trigger a match.
*/
resolver.registerContentObserver(URI, true, new MyObserver(new Handler()));
}
private class MyObserver extends ContentObserver{
public MyObserver(Handler handler) {
super(handler);
// TODO Auto-generated constructor stub
}
@Override
public void onChange(boolean selfChange) {
super.onChange(selfChange);
Toast.makeText(MainActivity.this, "数据库内容发送变化了！", 0).show();
}
}
}
posted on 2012-10-10 09:21 Freedom000 阅读(220) 评论(0) 编辑 收藏 举报
