Android开发之ProgressDialog在独立Thread线程中更新进度

简单的需求：在一个工作Thread中更新进度对话框ProgressDialog

遇到的问题：

1，创建需要Context，这个需要传进来

2，Thread中不能创建ProgressDialog，否则需要创建Looper

3，直接在Thread中更新ProgressDialog不行，扔例外，不是创建Thread的View不允许更新

4，Thread外创建Handler，然后现成里Post，更本不会更新。

解决方案：

1，创建ProgressDialog，同时创建Handler，用Callback handleMessage更新对话框

2，Thread中调用sendMessage之后，还需要调用Thread.yield()或Thread.sleep(),否则同样不更新。

示例代码：

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();