基础学习总结（六）--getContentRolver()的应用、内容监听者ContentObserver

ContentResolver / getContentResolver()

 

外界的程序通过ContentResolver接口可以访问ContentProvider提供的数据，在Activity当中通过getContentResolver()可以得到当前应用的 ContentResolver实例。ContentResolver提供的接口和ContentProvider中需要实现的接口对应，具体可以查看API Doc，不过可以发现ContentResolver里面的方法很多都是final或者static的。在实际应用中，我们很少实现ContentResolver抽象类，更多时候通过getContentResolver()从一个Activity或其它应用程序组件的实现里获取一个ContentResolver：

短信的uri地址:"content:\\sms\"

 1 public class MainActivity extends Activity {

 2 

 3     @Override

 4     protected void onCreate(Bundle savedInstanceState) {

 5         super.onCreate(savedInstanceState);

 6         setContentView(R.layout.activity_main);

 7         

 8     }

 9     

10     /*

11      * 备份短信点击事件*/

12     public void backupSms(View v){

13         //1.查出所有短信

14         Uri uri = Uri.parse("content://sms/");

15         //通过上下对象的getContentRolver方法获得ContentResolver实例

16         ContentResolver resolver = getContentResolver();

17         //获得游标Cursor对象

18         Cursor cor= resolver.query(uri, new String[]{"_id","address","date","type","body"}, null, null, null);

19         if(cor!=null&&cor.getCount()>0){

20             List<SmsInfo> list=new ArrayList<SmsInfo>();

21             SmsInfo sms;

22             while(cor.moveToNext()){

23                 sms=new SmsInfo();

24                 sms.setsId(cor.getInt(0));

25                 sms.setAddress(cor.getString(1));

26                 sms.setDate(cor.getLong(2));

27                 sms.setType(cor.getInt(3));

28                 sms.setBody(cor.getString(4));

29                 list.add(sms);

30             }

31             cor.close();

32             Log.w("MainActivity", "list中条数："+String.valueOf(list.size()));

33             //2.存到本地

34             writeToLocal(list);

35         }

36         

37         

38     }

39     

40     private void writeToLocal(List<SmsInfo> smslist){

41         

42         try {

43             XmlSerializer srlz= Xml.newSerializer();//得到序列化对象

44             /*动态获取sd卡地址

45              * String state=Environment.getExternalStorageState();

46             if(Environment.MEDIA_MOUNTED.equals(state)){

47                 return;

48             }

49             File sdcardFile=Environment.getExternalStorageDirectory();

50             File f=new File(sdcardFile,"sms.xml");*/

51             FileOutputStream fos=new FileOutputStream("/mnt/sdcard/sms.xml");

52             //将数据写入xml文本

53             srlz.setOutput(fos, "utf-8");

54             

55             srlz.startDocument("utf-8", true);

56             

57             srlz.startTag(null, "SmsInfo");

58             for (SmsInfo s : smslist) {

59                 srlz.startTag(null, "sms");

60                 srlz.attribute(null, "id", String.valueOf(s.getsId()));

61                 

62                 srlz.startTag(null, "address");

63                 srlz.text(s.getAddress());

64                 srlz.endTag(null, "address");

65                 

66                 srlz.startTag(null, "date");

67                 srlz.text(String.valueOf(s.getDate()));

68                 srlz.endTag(null, "date");

69                 

70                 srlz.startTag(null, "type");

71                 srlz.text(String.valueOf(s.getType()));

72                 srlz.endTag(null, "type");

73                 

74                 srlz.startTag(null, "body");

75                 srlz.text(s.getBody());

76                 srlz.endTag(null, "body");

77                 

78                 

79                 srlz.endTag(null, "sms");

80             }

81             

82             srlz.endTag(null, "SmsInfo");

83             

84             srlz.endDocument();

85             

86             Toast.makeText(this, "保存成功", 0).show();

87             

88         } catch (Exception e) {

89             Toast.makeText(this, "保存失败", 0).show();

90             e.printStackTrace();

91             

92         } 

93     }

94 }

备份短信实例

添加外部读写权限与本地读取权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

<uses-permission android:name="android.permission.READ_SMS"/>

联系人的uri地址：

content://com.android.contacts/raw_contacts
content://com.android.contacts/data

 

  1 public class MainActivity extends Activity {

  2 

  3     private static final String TAG = "MainActivity";

  4 

  5     @Override

  6     protected void onCreate(Bundle savedInstanceState) {

  7         super.onCreate(savedInstanceState);

  8         setContentView(R.layout.activity_main);

  9     }

 10 

 11     private void printCursor(Cursor cursor) {

 12         if(cursor != null && cursor.getCount() > 0) {

 13             

 14             while(cursor.moveToNext()) {

 15                 

 16                 int columnCount = cursor.getColumnCount(); // 列的总数

 17                 

 18                 for (int i = 0; i < columnCount; i++) {

 19                     String columnName = cursor.getColumnName(i);    // 取对应i位置的列的名称

 20                     String columnValue = cursor.getString(i); // 取出对应i位置的列的值

 21                     

 22                     Log.i(TAG, "当前是第" + cursor.getPosition() + "行: " + columnName + " = " + columnValue);

 23                 }

 24             }

 25             cursor.close();

 26         }

 27     }

 28 

 29     /**

 30      * 查询联系人

 31      * @param v

 32      */

 33     public void queryContacts(View v) {

 34         // 1. 去raw_contacts表中取所有联系人的_id

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

 36         Uri dataUri = Uri.parse("content://com.android.contacts/data");

 37         

 38         Cursor cursor = getContentResolver().query(uri, new String[]{"_id"}, null, null, null);

 39 //        printCursor(cursor);

 40         if(cursor != null && cursor.getCount() > 0) {

 41             

 42             while(cursor.moveToNext()) {

 43                 int id = cursor.getInt(0);

 44                 // 2. 去data表中根据上面取到的_id查询对应id的数据.

 45                 

 46                 //where语句

 47                 String selection = "raw_contact_id = ?";

 48                 //where语句需要的值

 49                 String[] selectionArgs = {String.valueOf(id)};

 50                     //                                                需要的字段

 51                 Cursor c = getContentResolver().query(dataUri, new String[]{"data1", "mimetype"}, 

 52                         selection, selectionArgs, null);

 53                 if(c != null && c.getCount() > 0) {

 54                     

 55                     while(c.moveToNext()) {

 56                         String mimetype = c.getString(1);        // 当前取的是mimetype的值

 57                         String data1 = c.getString(0);        // 当前取的是data1数据

 58                         

 59                         if("vnd.android.cursor.item/phone_v2".equals(mimetype)) {

 60                             Log.i(TAG, "号码: " + data1);

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

 62                             Log.i(TAG, "姓名: " + data1);

 63                         } else if("vnd.android.cursor.item/email_v2".equals(mimetype)) {

 64                             Log.i(TAG, "邮箱: " + data1);

 65                         }

 66                     }

 67                     c.close();

 68                 }

 69             }

 70             cursor.close();

 71         }

 72 

 73     }

 74     

 75     public void addContacts(View v) {

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

 77         Uri dataUri = Uri.parse("content://com.android.contacts/data");

 78         // 1. 在raw_contacts表中添加一个记录

 79         

 80         // 取raw_contacts表中contact_id的值

 81         Cursor cursor = getContentResolver().query(uri, new String[]{"contact_id"}, null, null, "contact_id desc limit 1");

 82         if(cursor != null && cursor.moveToFirst()) {

 83             int contact_id = cursor.getInt(0);

 84             contact_id ++;

 85             cursor.close();

 86             

 87             ContentValues values = new ContentValues();

 88             values.put("contact_id", contact_id);

 89             getContentResolver().insert(uri, values);

 90 

 91             // 2. 根据上面添加记录的id, 取data表中添加三条数据

 92             

 93             // 存号码

 94             values = new ContentValues();

 95             values.put("mimetype", "vnd.android.cursor.item/phone_v2");

 96             values.put("data1", "10086");

 97             values.put("raw_contact_id", contact_id);

 98             getContentResolver().insert(dataUri, values);

 99             

100             // 存姓名

101             values = new ContentValues();

102             values.put("mimetype", "vnd.android.cursor.item/name");

103             values.put("data1", "中国移动");

104             values.put("raw_contact_id", contact_id);

105             getContentResolver().insert(dataUri, values);

106             

107             // 存姓名

108             values = new ContentValues();

109             values.put("mimetype", "vnd.android.cursor.item/email_v2");

110             values.put("data1", "[email protected]");

111             values.put("raw_contact_id", contact_id);

112             getContentResolver().insert(dataUri, values);

113         }

114 

115     }

116 }

获取联系人

添加联系人的读写sd卡权限

<uses-permission android:name="android.permission.READ_CONTACTS"/>
<uses-permission android:name="android.permission.WRITE_CONTACTS"/>

 

ContentObServer应用：

1 首先创建一个ContentObserver的子类，然后实现里面的onChange方法，监听的Uri中的数据发生变化的时候，会调用onchange方法。

2 注册ContentObserver。

 1 public class MainActivity extends Activity {

 2 

 3     @Override

 4     protected void onCreate(Bundle savedInstanceState) {

 5         super.onCreate(savedInstanceState);

 6         setContentView(R.layout.activity_main);

 7         

 8         // 监听系统短信

 9         

10         ContentResolver resolver = getContentResolver();

11         

12         // 注册一个内容观察者观察短信数据库

13         resolver.registerContentObserver(Uri.parse("content://sms/"), true, new MyContentObserver(new Handler()));

14     }

15     

16     /**

17      * 内容观察者

18      */

19     class MyContentObserver extends ContentObserver {

20 

21         private static final String TAG = "MyContentObserver";

22 

23         public MyContentObserver(Handler handler) {

24             super(handler);

25         }

26 

27         /**

28          * 当被监听的内容发生改变时回调

29          */

30         @Override

31         public void onChange(boolean selfChange) {

32             Log.i(TAG, "短信改变了");

33             Uri uri = Uri.parse("content://sms/outbox");    // 发件箱的uri

34             

35             // 查询发件箱的内容

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

37             if(cursor != null && cursor.getCount() > 0) {

38                 

39                 String address;

40                 long date;

41                 String body;

42                 while(cursor.moveToNext()) {

43                     address = cursor.getString(0);

44                     date = cursor.getLong(1);

45                     body = cursor.getString(2);

46                     

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

48                 }

49                 cursor.close();

50             }

51         }

52     }

53 }

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