从Uri到ContentProvider详解

Uri

举例：content://org.crazyitxxxxx/words

协议部分：content：// 这部分是Android的ContentProvider规定默认协议
authorities部分，org.crazyitxxxxx ：ContentProvider的authorities.系统根据这个来操作那个ContentProvider。
资源部分：words。这部分是动态改变的。

Uri还支持content://org.crazyitxxxxx/words/2
含义：访问Word数据中ID为2的记录
Uri还支持content://org.crazyitxxxxx/words/2/word
含义：访问Word数据中ID为2的记录的Word字段

ContentProvider所操作的数据除了来自数据库，也可以来自文件，xml等网络存储。
ContentUri的withAppendId(uri,id)可以为路径加上id部分

parseId可以解析ID值

开发ContentProvider流程

创建ContentProvider子类，实现query(),insert(),update(),delete()方法
在AndroidManifest.xml文件中注册该ContentProvider，指定authorities属性。子元素<andorid:exported>指定是否能被其他应用调用
使用Context的getContentResolver()方法调用query（）,insert(),updata(),delete()方法，实际上就是调用对应的Uri的相应方法。

ContentProvider的保安UriMacher

创建



public static UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);、



注入Uri,以及指定的UriMacher对应的标志code

static {
uriMatcher.addURI(Constants.Authorities, "words", STATUS_WORDS);

uriMatcher.addURI(Constants.Authorities, "word/#", STATUS_WORD);
}

int match(uri) 根据注册的uri得到code

int status = uriMatcher.match(uri);

switch (status) {

case STATUS_WORDS:

rows = wdb.delete(Constants.DictTable.TABLE, selection, selectionArgs);

System.out.println("删除 完成 rows "+rows);

break;

case STATUS_WORD:

long id = ContentUris.parseId(uri);

String clause = Constants.DictTable.ID+" = "+id;

String conditions = clause +" and "+ selection;

rows = wdb.delete(Constants.DictTable.TABLE,conditions,selectionArgs);

System.out.println("rows :"+rows);

break;

}

监听ContentProvider的数据改变之ContentObserver

getContext().getContextResolver().notifyChange(uri,null);在insert，delete,update中导致数据改变，调用此方法，null，就会通知注册在该Uri上的所用ContentObserver
注册监听。getContentResolver().registerContentObserver(uri,boolean,Observer),实现Observer类重写回调方法OnChanged()

代码：

public class MainActivity extends Activity
{

@Override

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// 为content://sms的数据改变注册监听器

getContentResolver().registerContentObserver(

Uri.parse("content://sms"), true,

new SmsObserver(new Handler()));

}

// 提供自定义的ContentObserver监听器类

private final class SmsObserver extends ContentObserver

{

public SmsObserver(Handler handler)

{

super(handler);

}

public void onChange(boolean selfChange)

{

// 查询发送箱中的短信（处于正在发送状态的短信放在发送箱）

Cursor cursor = getContentResolver().query(

Uri.parse("content://sms/")

, null, null, null, null);

// 遍历查询得到的结果集，即可获取用户正在发送的短信

while (cursor.moveToNext())

{

StringBuilder sb = new StringBuilder();

// 获取短信的发送地址

sb.append("address=").append(cursor

.getString(cursor.getColumnIndex("address")));

// 获取短信的标题

sb.append(";subject=").append(cursor

.getString(cursor.getColumnIndex("subject")));

// 获取短信的内容

sb.append(";body=").append(cursor

.getString(cursor.getColumnIndex("body")));

// 获取短信的发送时间

sb.append(";time=").append(cursor

.getLong(cursor.getColumnIndex("date")));

System.out.println("发送短信：" + sb.toString());

}

}

}

- 系统的ContentProvider

- 管理联系人的ContentProvider

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

contactList = (ListView) findViewById(R.id.lv_contact);

initData();

}

private void initData() {

Uri consUri = ContactsContract.Contacts.CONTENT_URI;

Uri phoUri = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;

Uri emailUri = ContactsContract.CommonDataKinds.Email.CONTENT_URI;

Uri uri = Uri.parse("content://com.android.contacts");

Uri rawContactUri = uri.withAppendedPath(uri, "raw_contacts");

Uri dataUri = uri.withAppendedPath(uri, "data");

Uri mimeTypeUri = Uri.withAppendedPath(uri, "mimetypes");

Cursor rawContactCousor = getContentResolver().query(rawContactUri, new String[]{"contact_id"}, null, null, null);

while (rawContactCousor.moveToNext()) {

String contactId = rawContactCousor.getString(0);

System.out.println(contactId);

Cursor dataCursor = getContentResolver().query(dataUri, new String[]{"mimetype", "data1"}, "raw_contact_id = ?",new String[]{contactId}, null);

String mimeType = null;

while (dataCursor.moveToNext()) {

mimeType = dataCursor.getString(0);

// Cursor mimeTypeCursor = getContentResolver().query(mimeTypeUri, new String[]{"mimetype"}, "raw_contact_id = ?", new String[]{StringId}, null);

/* while (mimeTypeCursor.moveToNext()) {

mimeType = mimeTypeCursor.getString(0);

System.out.println("mimeType: " + mimeType);

}

mimeTypeCursor.close();*/

String type = null;

if ("vnd.android.cursor.item/email_v2".equals(mimeType)) {

type = "email";

} else if ("vnd.android.cursor.item/phone_v2".equals(mimeType)) {

type = "phomeNumber";

} else if ("vnd.android.cursor.item/name".equals(mimeType)) {

type = "name";

}

String data = dataCursor.getString(1);

System.out.println("name: "+type+" data: "+data);

}

dataCursor.close();

}

rawContactCousor.close();

}

2.获取短信数据：（区别于用Broadcast获取短信数据）

public class MainActivity extends AppCompatActivity {

private Uri smsUri;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
smsUri = Uri.parse("content://sms");
initData();
}

private void initData() {
Cursor smsCursor = getContentResolver().query(smsUri, null, null, null, null);
while(smsCursor.moveToNext()){
String address = smsCursor.getString(smsCursor.getColumnIndex("address"));
String body = smsCursor.getString(smsCursor.getColumnIndex("body"));
System.out.println("address: "+address+" body: "+body);
}
}
}