Android实现支持进度条显示的短信备份工具类

使用内容提供者读取短信内容，写入XML文件，进度条ProgressDialog更新备份进度。
新知识点：子线程如何在在不使用Handler的情况下更新UI

/** 
 *   进行短信备份的工具类，支持进度条显示 
 * @author lian 
 * 
 */ 
 
public class SmsBackupUtils { 
  private static class Data{ 
    int progress; 
  } 
   
  /** 
   * 
   * @param context 
   *   调用此工具类的Activity 
   * @param pd 
   *   显示备份进度的进度条 
   */ 
  public static void smsBackup(Activity context,final ProgressDialog pd){ 
    Uri uri = Uri.parse("content://sms/"); 
    ContentResolver cr = context.getContentResolver(); 
     
    //取出短信 
    final Cursor cursor = cr.query(uri, new String[]{"address","date","body","type"}, null, null, null); 
     
    final int count = cursor.getCount(); 
     
    final Data data = new Data(); 
    data.progress = 0; 
     
    //存储路径 
    File file = new File(Environment.getExternalStorageDirectory(), "sms.xml"); 
    try { 
      FileOutputStream fos = new FileOutputStream(file); 
      PrintWriter pw = new PrintWriter(fos); 
       
      //按照XML格式进行写入 
      pw.println(""); 
       
      //在主线程中更新UI 
      context.runOnUiThread(new Runnable() { 
         
        @Override 
        public void run() { 
          // TODO Auto-generated method stub 
          pd.setMax(count); 
          pd.show(); 
        } 
      }); 
       
      //写入XML文件 
      while(cursor.moveToNext()){ 
        data.progress ++; 
        String address = cursor.getString(0); 
        String date = cursor.getString(1); 
        String body = cursor.getString(2); 
        String type = cursor.getString(3); 
         
        //SystemClock.sleep(150); 
        pw.println(""); 
        pw.println("
"+ address +"
"); 
        pw.println(""+ date +""); 
        pw.println(""+ body +""); 
        pw.println(""+ type +""); 
        pw.println(""); 
         
        context.runOnUiThread(new Runnable() { 
           
          @Override 
          public void run() { 
            // TODO Auto-generated method stub 
            pd.setProgress(data.progress); 
          } 
        }); 
         
      } 
      pw.println(""); 
      pw.flush(); 
      pw.close(); 
      cursor.close(); 
      //备份完成，关闭进度条 
      context.runOnUiThread(new Runnable() { 
        @Override 
        public void run() { 
          // TODO Auto-generated method stub 
          pd.dismiss(); 
        } 
      }); 
    } catch (Exception e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
    } 
     
     
  } 
} 

调用

pd = new ProgressDialog(this); 
pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); 
 
SmsBackupUtils.smsBackup(SuperToolActivity.this, pd); 

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