java - 线程 : start, 挂起、恢复

Question

我正在制作一个 Android 应用程序(最小 SDK:8，目标 SDK:19)

现在我想设置一个加载图标在开始时显示，直到应用程序检查互联网连接性

到目前为止我没有任何问题

我有这个方法为我做:

void setLoader(boolean T, String msg){
    View LAY = findViewById(R.id.loaderLayout);
    TextView MTV = (TextView) findViewById(R.id.loader_msg);
    if(T && !loaderStarted){
        loader.start();
        LAY.setVisibility(View.VISIBLE);
        MTV.setText(msg);
        loaderStarted = true;
    }
    else if (!T && loaderStarted) {
        loader.interrupt();
        LAY.setVisibility(View.GONE);
        loaderStarted = false;
    }
}

然后我需要获取用户和密码，然后再次使用该线程锁定 UI 以检查用户和密码 问题是 : 我在暂停线程时遇到问题:| 我的主要编程语言不是 java

所以请帮我解决这个问题，我有这样的线程:

//first make loading icon visible then call :

    final private Thread loader = new Thread(new Runnable(){

    @Override
    public void run() {
        int i = 0;
        while (true){
            if(loader.isInterrupted()){
                return;
                }
            try {Thread.sleep(25);} catch (InterruptedException e) {}
            final int j = i;
            runOnUiThread(new Runnable(){
                public void run() {
                    ImageView imageView = (ImageView) findViewById(R.id.loaderImage);
                    Matrix matrix = new Matrix();
                    imageView.setScaleType(ScaleType.MATRIX);
                    int newWIDTH = imageView.getWidth();
                    int newHIEGHT = imageView.getHeight();
                    matrix.postScale(((float)(newWIDTH))/imageView.getDrawable().getBounds().width(), ((float)(newHIEGHT))/imageView.getDrawable().getBounds().height());
                    matrix.postRotate((float) j, newWIDTH/2, newHIEGHT/2);
                    imageView.setImageMatrix(matrix);
                }   
            });
            i = (i + 15) % 360;
        }
    }
});

那么我需要这样的方法:

void setLoader(boolean T, String msg){
    View LAY = findViewById(R.id.loaderLayout);
    TextView MTV = (TextView) findViewById(R.id.loader_msg);
    if(T && !loaderStarted){
        loader.start();
        LAY.setVisibility(View.VISIBLE);
        MTV.setText(msg);
        loaderStarted = true;
    }
    else if(T && loaderSuspended && loaderStarted){
        loader.resume();
        LAY.setVisibility(View.VISIBLE);
        MTV.setText(msg);
        loaderSuspended = false;
    }
    else if (loaderStarted && !loaderSuspended) {
        loader.suspend();
        LAY.setVisibility(View.GONE);
        loaderStarted = false;
        loaderSuspended = true;
    }
}

暂停线程然后恢复它 (.suspend() 和 .resume() 已弃用)

提前致谢:) 对于糟糕的英语感到抱歉(:D)

Answer 1

您可以尝试添加字段:

// defines the paused state
private volatile boolean isPaused = false;

// a monitor object for wait/notify pattern
private final Object suspender = new Object();

然后按照你的逻辑:

void pause(){
     synchronized(suspender){
         isPaused = true;        
     }
}

void resume(){
     synchronized(suspender){
         isPaused = false;
         suspender.notify();
     }
}

while (true){
    if(loader.isInterrupted()){
        return;
    }

    // this outside loop is needed to deal with spurious wakeup
    synchronized (suspender){
        while(isPaused){            
            suspender.wait();
        }
    }

    ...
}

有关等待和通知的更多信息:A simple scenario using wait() and notify() in java