Android開發之ProgressDialog在獨立Thread線程中更新進度

標籤：

簡單的需求：在一個工作Thread中更新進度對話方塊ProgressDialog

遇到的問題：

1，建立需要Context，這個需要傳進來

2，Thread中不能建立ProgressDialog，否則需要建立Looper

3，直接在Thread中更新ProgressDialog不行，扔例外，不是建立Thread的View不允許更新

4，Thread外建立Handler，然後現成裡Post，更本不會更新。

解決方案：

1，建立ProgressDialog，同時建立Handler，用Callback handleMessage更新對話方塊

2，Thread中調用sendMessage之後，還需要調用Thread.yield()或Thread.sleep(),否則同樣不更新。

範例程式碼：

    final ProgressDialog pgDlg=new ProgressDialog(mContext);    pgDlg.setTitle("Testing ...");pgDlg.setMessage(" ");    pgDlg.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);    pgDlg.setIndeterminate(false);    pgDlg.setMax(100);pgDlg.setProgress(0);    pgDlg.setIcon(android.R.drawable.ic_menu_search);    final  Handler dlgHandler=new Handler(new Handler.Callback() {      @Override      public boolean handleMessage(Message msg) {        String s = (String)msg.obj;        pgDlg.setMessage(s);        if(msg.what>=100){          pgDlg.setProgress(100);          new Handler().postDelayed(new Runnable() {            @Override            public void run() {              pgDlg.dismiss();            }          },1000);        }else{          pgDlg.setProgress(msg.what);        }        return true;      }    });    pgDlg.show();    new Thread(new Runnable() {      @Override      public void run() {        BluetoothGattCharacteristic ctc=bleHelper.getCharacteristic(SampleGattAttributes.SERVICE_KeyService,SampleGattAttributes.CHARACTERISTIC_KeyCharacteristic);        for (int i=0;i<cmdsToTest.length;i++){          String cmd = cmdsToTest[i];          final String msg=String.format("command>：%s", cmd);          AppUtils.logD(msg);          ObdCommand oc = new ObdCommand(cmd, cmd);          final ObdCommandJob job = new ObdCommandJob(oc);          CommandExecutor executor = new BleCommandExecutor(bleHelper,ctc, job) .setLocker(mJobLock, mJobCondition);          try {            mJobLock.lock();            new Thread(executor).start();            mJobCondition.await(5, TimeUnit.SECONDS);          } catch (InterruptedException ex) {            Log.e("", ex.getMessage());            job.setState(ObdCommandJobState.EXECUTION_ERROR);          } finally {            mJobLock.unlock();            bleHelper.resumeIO();          }          if (job.getState() != ObdCommandJobState.FINISHED) {            errorMsg = String.format("test command %s failed!", job.getCommand().getCommand());            if (resultListener != null) {              resultListener.onTestDone(false, errorMsg);              Message.obtain(dlgHandler,100,errorMsg).sendToTarget();              Thread.yield();
　　　　　　　　break;            }          }          final int progress = i*100/cmdsToTest.length;          Message.obtain(dlgHandler,progress,msg+"\nresult>:"+job.getCommand().getRawData()).sendToTarget();          //pgDlg.setMessage(msg);  throw exception when access direct here          //pgDlg.incrementProgressBy(progress );          Thread.yield();//must yield to let message processed        }        if (resultListener != null) {          resultListener.onTestDone(true, "");          Message.obtain(dlgHandler,100,"done").sendToTarget();          Thread.yield();        }        bleHelper.close();      }    }).start();

 

Android開發之ProgressDialog在獨立Thread線程中更新進度