ContentProvider ContentResolver ContentObserver 内容：提供、访问、监听

内容提供

public class PersonContentProvider extends ContentProvider{

private static final String AUTHORITY = "com.itheima28.sqlitedemo.providers.PersonContentProvider";
 private static final int PRESON_INSERT_CODE = 0; // 操作person表添加的操作的uri匹配码

UriMatcher uriMatcher;

private PersonSQLiteOpenHelper mOpenHelper;

static{

uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

uriMatcher.addURI(AUTHORITY, "person/insert", PRESON_INSERT_CODE);

}

@Override
 public boolean onCreate() {
  mOpenHelper = new PersonSQLiteOpenHelper(getContext());
  return true;
 }

@Override
 public Uri insert(Uri uri, ContentValues values) {
  
  switch (uriMatcher.match(uri)) {
  case PRESON_INSERT_CODE: // 添加人到person表中
   SQLiteDatabase db = mOpenHelper.getWritableDatabase();
   
   if(db.isOpen()) {
    
    long id = db.insert("person", null, values);
    
    db.close();
    
    return ContentUris.withAppendedId(uri, id);
   }
   break;
  default:
   throw new IllegalArgumentException("uri不匹配: " + uri);
  }
  return null;
 }

}

UriMatcher

内容访问

ContentResolver resolver = getContext().getContentResolver();

uri = resolver.insert(uri, values);

int count = resolver.delete(uri, where, selectionArgs);

int count = resolver.update(uri, values, "_id = ?", new String[]{"20"});

Cursor cursor = resolver.query(uri, new String[]{"_id", "name", "age"}, null, null, "_id desc");

内容监听

resolver.registerContentObserver(Uri.parse("content://sms/"), true, new MyContentObserver(new Handler()));   //注册内容监听

class MyContentObserver extends ContentObserver {

private static final String TAG = "MyContentObserver";

public MyContentObserver(Handler handler) {

super(handler);

}

/**    * 当被监听的内容发生改变时回调    */

@Override

public void onChange(boolean selfChange) {

Log.i(TAG, "短信改变了");

Uri uri = Uri.parse("content://sms/outbox"); // 发件箱的uri        // 查询发件箱的内容

Cursor cursor = getContentResolver().query(uri, new String[]{"address", "date", "body"}, null, null, null);

if(cursor != null && cursor.getCount() > 0) {          String address;     long date;     String body;

while(cursor.moveToNext()) {      address = cursor.getString(0);      date = cursor.getLong(1);      body = cursor.getString(2);

Log.i(TAG, "号码: " + address + ", 日期: " + date + ", 内容: " + body);     }

cursor.close();

}   }  }