持续更新 android Textview

Question

我正在开发一个 Android 应用程序，它有一个 activity class 和 service class。在 service 中，将每 10 毫秒接收一次连续批量 data (1090 bytes)。我需要使用这些批量数据不断更新 text view。从连续后台服务更新 Text view 的推荐方法是什么？

服务Class

public class RecepService extends Service {

public static Handler mHandler;
StringBuilder hexstring;

@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public void onCreate() {
    super.onCreate();

    init();
}

private void init() {

    mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 0x123) {

                byte[] readBuf = (byte[]) msg.obj;
                int readBuflen = msg.arg1;

                // here will receive 1090 bytes of data 
                // every 10 milliseconds
                Receivepatientattributes(readBuf,readBuflen);
            }
        }
    };
}

public void Receivepatientattributes(byte[] readBuf, int len) {

    String total_data = "";
    total_data = bytetohex(readBuf, len);
    MainActivity.recep.setText(MainActivity.recep.getText().toString() + "\t" +
            "" + total_data );
}

String bytetohex(byte[] txt, int len) {

    String p="";
    byte[] text = new byte[len];
    text = txt;

    hexstring = new StringBuilder();
    for (int j = 0; j < len; j++) {

        String hex= Integer.toHexString(0xFF & txt[j]);

        if (hex.length()==1) {
            hexstring.append("0");
        }

        hexstring.append(hex+" ");

    }

    p=p+hexstring.toString();
    return p;
}

@Override
public void onDestroy() {
    super.onDestroy();
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    return START_STICKY;
}
}

Answer 1

您可以使用 Timer 持续更新您的文本视图。

每次当您的服务是运行最新值时，在首选项中设置值。

现在在 Timer 中从首选项中获取该值并使用该值更新您的 TextView。

这是一些代码：

class UpdateTimeTask extends TimerTask {
   public void run() {

   textview.setText("updated value");
   }
}

在onCreate()中设置；

    Timer timer = new Timer();
    UpdateTimeTask  UpdateTimeTask = new UpdateTimeTask ();
    timer.schedule(UpdateTimeTask, 1000);

Answer 2

用户 LocalBroadcastManager

public void Receivepatientattributes(byte[] readBuf, int len) {
    String total_data = "";
    total_data = bytetohex(readBuf, len);

    Intent intent = new Intent("update-text");
    // add data
    intent.putExtra("message", total_data);
    LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}

在 MainActivity 中

@Override
public void onResume() {
  super.onResume();

  // Register mMessageReceiver to receive messages.
  LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver,
      new IntentFilter("update-text"));
}

private boolean mCanBeUpdated = true;
private static final int ONE_SEC = 1000; //ms
private static final int RECEPTION_SPEED = 10; //ms
private static final int CYCLES = (int) (ONE_SEC / RECEPTION_SPEED);
private int mCurrentCycle = -1;
private String mMsgCache = "";

// handler for received Intents for the "update-text" event 
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        // Extract data included in the Intent
        String message = intent.getStringExtra("message");
        Log.d("receiver", "Got message: " + message);

        mMsgCache = mMsgCache + "\t" + message;

        if (mCanBeUpdated) {
            // No problem updating UI here, refer --> 
            final Handler handler = new Handler(context.getMainLooper());
            handler.post(new Runnable() {
                @Override
                public void run() {
                    MainActivity.recep.append(mMsgCache);
                    mMsgCache = "";
                }
            });

            mCanBeUpdated = false;
        } else if (mCurrentCycle >= CYCLES) {
            mCurrentCycle = -1;
            mCanBeUpdated = true;
        } else {
            mCurrentCycle++;
        }
    }
};

@Override
protected void onPause() {
  // Unregister since the activity is not visible
  LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
  super.onPause();
}

Reference

Answer 3

如果你想使用日程表和定时任务那么你可以See My Answer

要解决当前问题，请按照以下说明操作。假设您的 activity 有一个广播接收器

private BroadcastReceiver mReceiver;

然后你覆盖方法 onResume() 你的广播接收器将被注册的地方以及你的接收器将被注销的地方 onPause():

@Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();

        IntentFilter intentFilter = new IntentFilter(
                "android.intent.action.MAIN");

        mReceiver = new BroadcastReceiver() {

            @Override
            public void onReceive(Context context, Intent intent) {
                //extract your message from intent
                String msg_for_me = intent.getStringExtra("YOUR_MESSAGE");
                //log your message value
                Log.i("MyTag", msg_for_me);

            }
        };
        //registering your receiver
        this.registerReceiver(mReceiver, intentFilter);
    }

    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        super.onPause();
        //unregister your receiver
        this.unregisterReceiver(this.mReceiver);
    }

此处广播接收器通过 android.intent.action.MAIN 过滤，来自服务的消息将使用此过滤器进行广播

现在您的方法 Receivepatientattributes 会像这样：

public void Receivepatientattributes(byte[] readBuf, int len) {

    String total_data = "";
    total_data = bytetohex(readBuf, len);

    Intent i = new Intent("android.intent.action.MAIN").putExtra("YOUR_MESSAGE",  total_data);
    this.sendBroadcast(i);

}

就是这样。 :)

Answer 4

使用处理程序，因为处理程序允许从其他后台线程与 UI 线程进行通信。

boolean handlerStop = false;

    void handleHandler(){
        Handler handler =new Handler();
        final Runnable r = new Runnable() {
            public void run() {
                handler.postDelayed(this, 30000);
                if(!handlerStop) {
                    updateTextView() //update your text with other thread like asyncronous thread
                }
            }
        };
        handler.postDelayed(r, 0000);
    }

    @Override
    public void onResume() {
        super.onResume();
        handlerStop=false;
        handleHandler();
    }

    @Override
    public void onPause() {
        super.onPause();
        handlerStop=true;
        handleHandler();
    }

    @Override
    public void onStop() {
        super.onStop();
        handlerStop=true;
        handleHandler();
    }

持续更新 android Textview

Update android Textview continuously

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android-service

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