我正在开发一个安卓应用，它有一个简单易用的功能。activity 阶级和 service 类。在 service, 连续性散装 data (1090 bytes) 将每10毫秒接收一次。我需要更新 text view 连续使用这些批量数据。推荐的更新方式是什么？Text view 从连续后台服务?
服务类
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;
}
}
如果你想使用时间表和定时器任务，那么你可以 查看我的回答
假设你的活动有一个广播接收器，要解决目前的问题，请按照下面的说明进行。
private BroadcastReceiver mReceiver;
然后你覆盖方法 onResume() 您的广播接收机将在哪里注册，以及 onPause() 你的接收器将在哪里被取消注册。
@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);
}
这里的广播接收器是通过 android.intent.action.MAIN 并从服务中使用这个过滤器来广播信息。
现在你的方法 Receivepatientattributes 会喜欢这个。
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:)
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 --> http://stackoverflow.com/a/5676888/1008278
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();
}
您可以使用 定时器 用于持续更新您的文本视图。
在偏好设置中设置每次服务运行时的最新值。
现在，在Timer中从偏好设置中获取该值，并以该值更新你的TextView。
下面是一些代码。
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);
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();
}