在下面的代码中，我维护“isFound”布尔变量来确定线程是否应该运行。但是，当我将“isFound”设置为true时。我的线程将再次运行一次。换句话说，它们将无法正常停止，这也会导致UI无法正确更新Textview。我想这是由于一些同步的问题，但我不知道如何处理它，我尝试使用同步块，但它仍然无法正常工作。
import android.app.Notification;
import android.app.NotificationManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.ProgressBar;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private ProgressBar progressBar;
private TextView message;
private TextView magicNumDisplay;
private boolean isFound = false;
private NotificationManager notificationManager;
private Notification notifyDetail;
private final Handler handler = new Handler(){
public void handleMessage(Message msg) {
if (isMagic(msg.what)) {
isFound = true;
progressBar.setVisibility(View.INVISIBLE);
magicNumDisplay.setText("The magic number is " + msg.what);
handler.removeMessages(0);
message.setText("A magic number s found");
Intent intent = new Intent("MAGIC_NUMBER");
intent.putExtra("THREAD_NAME", msg.obj.toString());
intent.putExtra("MAGIC_NUMBER", String.valueOf(msg.what));
sendBroadcast(intent);
} else {
message.setText("Finding a magic number...");
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
message = (TextView) findViewById(R.id.message);
progressBar = (ProgressBar) findViewById(R.id.progressbar);
magicNumDisplay = (TextView) findViewById(R.id.magic_num_display);
progressBar.setVisibility(View.VISIBLE);
IntentFilter filter = new IntentFilter("MAGIC_NUMBER");
BroadcastReceiver receiver = new MagicNumberReceiver();
registerReceiver(receiver, filter);
notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
}
public void onStart(){
super.onStart();
Thread firstThread = new Thread(backgroundTask, "First");
Thread secondThread = new Thread(backgroundTask, "Second");
firstThread.start();
secondThread.start();
}
public boolean isMagic(int num) {
return (num % 7 == 0 && isLastDigitEqualTwo(num));
}
public boolean isLastDigitEqualTwo(int num) {
String numString = String.valueOf(num);
return Integer.parseInt(numString.substring(numString.length() - 1))==2;
}
Runnable backgroundTask = new Runnable() {
@Override
public void run() {
try {
while (!isFound) {
Thread.sleep(1000);
int number = (int) (Math.random() * 9999);
Message msg = handler.obtainMessage(number, Thread.currentThread().getName());
handler.sendMessage(msg);
Log.e(Thread.currentThread().getName(), "The number is :" + number);
}
} catch(InterruptedException e){
Log.e("Exception", e.getMessage());
}
}
};
public class MagicNumberReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context localContext, Intent callerIntent) {
String threadName = callerIntent.getStringExtra("THREAD_NAME");
String magicNum = callerIntent.getStringExtra("MAGIC_NUMBER");
Log.e("Magic", "Thread name:"+threadName+" Magic Number:"+magicNum);
int MAGIC_NUMBER_NOTIFICATION_ID=200;
notifyDetail = new Notification.Builder(getApplicationContext())
.setContentTitle("Magic Number")
.setContentText("Thread Name: " + threadName + ". Magic Number: " + magicNum+".")
.setSmallIcon(R.drawable.droid)
.setVibrate(new long[] {1000, 1000, 1000, 1000})
.setLights(Integer.MAX_VALUE, 500, 500)
.build();
notificationManager.notify(MAGIC_NUMBER_NOTIFICATION_ID,notifyDetail);
}
}
}