Android 4.2.1 - 以编程方式更新 APN 设置数据库中的列

Question

我正在尝试更新位于以下位置的首选 APN 数据库表的“名称”列:content://telephony/carriers/preferapn。但是，我的应用程序的 ContentResolver.update() 始终返回 0，这意味着没有更新任何行。我已经拥有该应用程序的 root 访问权限，并在运行 update() 之前以编程方式确认了它。

可以找到有关表列的详细信息here和 here .我还确保引用了 documentation关于如何调用更新功能。

更新方法:

public boolean setAPN(String newAPN, TextView t){

    //get URI objects for the tables
    final Uri APN_TABLE_URI = Uri.parse("content://telephony/carriers");
    final Uri PREFERRED_APN_URI = Uri.parse("content://telephony/carriers/preferapn");

    //Confirm permissions
    PackageManager pm = getPackageManager();
    if (pm.checkPermission(permission.WRITE_APN_SETTINGS, getPackageName()) == PackageManager.PERMISSION_GRANTED) {

        //Update name field
        ContentResolver resolver = this.getContentResolver();
        ContentValues values = new ContentValues();          
        values.put("name", newAPN);
        long rc = resolver.update(PREFERRED_APN_URI, values, null, null);

        //Display the row contents (always has the original fields, doesn't update)
        Cursor c = getContentResolver().query(PREFERRED_APN_URI, null, null, null, null);
        c.moveToFirst();         
        int index = c.getColumnIndex("_id");    //getting index of required column
        Short id = c.getShort(index);           //getting APN's id from        
        index = c.getColumnIndex("name");
        String name = c.getString(index);        
        index = c.getColumnIndex("mcc");
        String mcc = c.getString(index);        
        index = c.getColumnIndex("mnc");
        String mnc = c.getString(index);        
        index = c.getColumnIndex("numeric");
        String numeric = c.getString(index);

        t.setText(" ID:" + id + "\n" + 
              " APN Name: " + name + "\n" +
              " MCC: " + mcc + "\n" +
              " MNC: " + mnc + "\n" +
              " Numeric: " + numeric + "\n"

            );

    } else { 
        t.setText(" You don't have permission to do this. ");    
    }

    return true;
}

如前所述，我也有权限: list 文件中的“android.permission.WRITE_APN_SETTINGS”:

我是否出于特定目的错误地调用了更新函数？还是使用 update() 是错误的方法？

Answer 1

这个问题已经死了快一个月了，但我为这个问题做了一个解决方法并想分享它。解决方法包括复制不包括名称字段的现有首选 APN 条目，将新 APN 插入运营商列表，然后使用新生成的 ID 将新 APN 设置为首选。

public int InsertAPN(String name){      

    //Set the URIs and variables
    int id = -1;
    boolean existing = false;
    final Uri APN_TABLE_URI = Uri.parse("content://telephony/carriers");
    final Uri PREFERRED_APN_URI = Uri.parse("content://telephony/carriers/preferapn");

    //Check if the specified APN is already in the APN table, if so skip the insertion                      
    Cursor parser = getContentResolver().query(APN_TABLE_URI, null, null, null, null);
    parser.moveToLast();            
    while (parser.isBeforeFirst() == false){
        int index = parser.getColumnIndex("name");
        String n = parser.getString(index);   
        if (n.equals(name)){
            existing = true;   
            Toast.makeText(getApplicationContext(), "APN already configured.",Toast.LENGTH_SHORT).show();
            break;
        }            
        parser.moveToPrevious();
    }       

    //if the entry doesn't already exist, insert it into the APN table      
    if (!existing){         

           //Initialize the Content Resolver and Content Provider
           ContentResolver resolver = this.getContentResolver();
           ContentValues values = new ContentValues();

           //Capture all the existing field values excluding name
           Cursor apu = getContentResolver().query(PREFERRED_APN_URI, null, null, null, null);
           apu.moveToFirst();                   
           int index;       

           index = apu.getColumnIndex("apn");
           String apn = apu.getString(index);               
           index = apu.getColumnIndex("type");
           String type = apu.getString(index);              
           index = apu.getColumnIndex("proxy");
           String proxy = apu.getString(index);             
           index = apu.getColumnIndex("port");
           String port = apu.getString(index);               
           index = apu.getColumnIndex("user");
           String user = apu.getString(index);              
           index = apu.getColumnIndex("password");
           String password = apu.getString(index);              
           index = apu.getColumnIndex("server");
           String server = apu.getString(index);                
           index = apu.getColumnIndex("mmsc");
           String mmsc = apu.getString(index);             
           index = apu.getColumnIndex("mmsproxy");
           String mmsproxy = apu.getString(index);              
           index = apu.getColumnIndex("mmsport");
           String mmsport = apu.getString(index);               
           index = apu.getColumnIndex("mcc");
           String mcc = apu.getString(index);               
           index = apu.getColumnIndex("mnc");
           String mnc = apu.getString(index);               
           index = apu.getColumnIndex("numeric");
           String numeric = apu.getString(index);

           //Assign them to the ContentValue object
           values.put("name", name); //the method parameter
           values.put("apn", apn);                 
           values.put("type", type);
           values.put("proxy", proxy);
           values.put("port", port);
           values.put("user", user);
           values.put("password", password);
           values.put("server", server);
           values.put("mmsc", mmsc);
           values.put("mmsproxy", mmsproxy);
           values.put("mmsport", mmsport);             
           values.put("mcc", mcc);
           values.put("mnc", mnc);
           values.put("numeric", numeric);             

           //Actual insertion into table
           Cursor c = null;
           try{
               Uri newRow = resolver.insert(APN_TABLE_URI, values);

               if(newRow != null){
                   c = resolver.query(newRow, null, null, null, null);
                    int idindex = c.getColumnIndex("_id");
                    c.moveToFirst();
                    id = c.getShort(idindex);                       
               }
           }
           catch(SQLException e){}
           if(c !=null ) c.close();          
    }

    return id;
}

//Takes the ID of the new record generated in InsertAPN and sets that particular record the default preferred APN configuration
public boolean SetPreferredAPN(int id){

    //If the id is -1, that means the record was found in the APN table before insertion, thus, no action required
    if (id == -1){
        return false;
    }

    Uri.parse("content://telephony/carriers");
    final Uri PREFERRED_APN_URI = Uri.parse("content://telephony/carriers/preferapn");

    boolean res = false;
    ContentResolver resolver = this.getContentResolver();
    ContentValues values = new ContentValues();

    values.put("apn_id", id); 
    try{
        resolver.update(PREFERRED_APN_URI, values, null, null);
        Cursor c = resolver.query(PREFERRED_APN_URI, new String[]{"name", "apn"}, "_id="+id, null, null);
        if(c != null){
            res = true;
            c.close();
        }
    }
    catch (SQLException e){}
     return res;
}

然后您可以像这样调用该方法:

int identity = InsertAPN(NEW_APN_NAME); 
SetPreferredAPN(identity);