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我有一個運行無限的任務的子線程。我想（1）不斷地將數據發送回UI線程，（2）偶爾向子線程發送數據（對應於按鈕）以暫停/繼續無限任務。我的問題是，子線程卡在循環中，意味着任務不執行。Android - 循環後的代碼
我的問題是這樣的：如何讓子線程從UI線程接收消息而不阻塞無限任務？
這是我到目前爲止： 對於任務（1），我在我的UI線程中有一個處理程序，它的工作原理和子線程中的一個無限循環，它發送一條消息，它本身起作用。
在UI線程：
mMainHandler = new Handler() {
public void handleMessage(Message msg) {
Bundle b;
b = msg.getData();
if (msg.what==1)
Log.i("main", "from child (running) - " + b.getBoolean("running"));
else if (msg.what == 2)
Log.i("main", "from child (count) - " + b.getInt("count"));
}
};
在子線程（目前使用虛擬任務，直到我得到的框架制定）：
while (true) {
if (running) {
try {
curCount += up;
if (curCount == maxCount)
up = -1;
else if (curCount == minCount)
up = 1;
Thread.sleep(1000);
} catch (InterruptedException e) {
Log.e("", "local Thread error", e);
}
Bundle b = new Bundle(1);
b.putInt("count", curCount);
Message toMain = mMainHandler.obtainMessage();
toMain.what = 2;
toMain.setData(b);
mMainHandler.sendMessage(toMain);
}
}
有關任務（2），我有一個方法在我的UI線程中，對應於按鈕的按鈕，將消息發送到子線程，該子線程工作，並且子線程中的處理程序自行工作。
在UI線程：
private void sendRunning(boolean running) {
if (mChildHandler != null) {
Bundle b = new Bundle(1);
b.putBoolean("running", running);
Message msg = mChildHandler.obtainMessage();
msg.what = 1;
msg.setData(b);
mChildHandler.sendMessage(msg);
}
}
在子線程：
Looper.prepare();
mChildHandler = new Handler() {
public void handleMessage(Message msg) {
Bundle b;
if (msg.what==1){
b = msg.getData();
running = b.getBoolean("running");
Log.i(INNER_TAG, "from main (running) - " + b.getBoolean("running"));
Log.i(INNER_TAG, "running - " + running);
try {
Message toMain = mMainHandler.obtainMessage();
toMain.what = 1;
toMain.setData(b);
mMainHandler.sendMessage(toMain);
} finally {}
}
}
};
Looper.loop();
每個這些情況的一個正常工作獨自一人，而是試圖在同一時間做兩件事就是問題所在。如果我在Looper.loop（）之後放置了無限任務，它永遠不會到達。如果我把它放在Looper.prepare（）之前，它會運行一次。如果我把它放在彎鉤上，它仍然只能運行一次。
任何想法，將不勝感激:)
這裏是我完整的代碼（減去包裝/進口），僅供參考：
public class MainActivity extends Activity {
Thread thread;
private Handler mMainHandler, mChildHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mMainHandler = new Handler() {
public void handleMessage(Message msg) {
Bundle b;
b = msg.getData();
if (msg.what==1)
Log.i("main", "from child (running) - " + b.getBoolean("running"));
else if (msg.what == 2)
Log.i("main", "from child (count) - " + b.getInt("count"));
}
};
thread = new ChildThread();
thread.start();
// Get a reference to the button
Button buttonStart = (Button)findViewById(R.id.btnStart);
Button buttonStop = (Button)findViewById(R.id.btnStop);
// Set the click listener to run my code
buttonStart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this,
"Starting...", Toast.LENGTH_SHORT).show();
sendRunning(true);
}
});
buttonStop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this,
"Stopping...", Toast.LENGTH_SHORT).show();
sendRunning(false);
}
});
}
private void sendRunning(boolean running) {
if (mChildHandler != null) {
Bundle b = new Bundle(1);
b.putBoolean("running", running);
Message msg = mChildHandler.obtainMessage();
msg.what = 1;
msg.setData(b);
mChildHandler.sendMessage(msg);
}
}
@Override
protected void onDestroy() {
Log.i("tag", "stop looping the child thread's message queue");
mChildHandler.getLooper().quit();
super.onDestroy();
}
class ChildThread extends Thread {
private static final String INNER_TAG = "ChildThread";
private boolean running = true;
final int maxCount = 10;
final int minCount = 0;
public int curCount = minCount;
private int up = 1;
public void run() {
while (true) {
if (running) {
try {
curCount += up;
if (curCount == maxCount)
up = -1;
else if (curCount == minCount)
up = 1;
Thread.sleep(1000);
} catch (InterruptedException e) {
Log.e("", "local Thread error", e);
}
Bundle b = new Bundle(1);
b.putInt("count", curCount);
Message toMain = mMainHandler.obtainMessage();
toMain.what = 2;
toMain.setData(b);
mMainHandler.sendMessage(toMain);
}
this.setName("child");
Looper.prepare();
mChildHandler = new Handler() {
public void handleMessage(Message msg) {
Bundle b;
if (msg.what==1){
b = msg.getData();
running = b.getBoolean("running");
Log.i(INNER_TAG, "from main (running) - " + b.getBoolean("running"));
Log.i(INNER_TAG, "running - " + running);
try {
Message toMain = mMainHandler.obtainMessage();
toMain.what = 1;
toMain.setData(b);
mMainHandler.sendMessage(toMain);
} finally {}
}
}
};
Log.i(INNER_TAG, "Child handler is bound to - " +
mChildHandler.getLooper().getThread().getName());
Looper.loop();
}
}
}
}
備註：我花了一段時間研究並試圖弄清楚如何使用線程，並且[this]（http://codinghard.wordpress.com/2009/05/16/android-thread-messaging/）頁面奠定了非常好的。 [This]（http://www.biemmeitalia.net/blog/bundle-android/）頁面向我展示瞭如何使用bundle在線程之間交換數據。 – Andy
如果儘可能避免無限期地運行線程... – JoxTraex