Question

我希望在完成所有三个线程后执行方法uploadingDone()。这些标志大部分时间都正常工作。在极少数情况下，所有三个标志都设置为true，BLOCK1执行两次。所有三个线程都在不同的数据上执行不同的任务（不会发生并发修改）。

我可以在线程上删除任何本机函数的标志吗？

所有三个线程并行运行（强制性要求）。 BLOCK1应该只被称为。

private synchronized void uploadingDone(){

    if( isItemUploaded && isListUploaded && isStoreUploaded){
        uploadingDone = true;
         //<BLOCK1>
        //TODO move to next screen
    }else{
        Log.i(TAG, "uploadingDone: Failed");
    }
}

private boolean isListUploaded = false, isItemUploaded = false, isStoreUploaded = false, uploadingDone = false;


private class ListUpload extends Thread{

    @Override
    public void run() {
        isListUploaded = true;
        Log.i(TAG, "ListUpload Thread started");
        if(!uploadingDone)
            uploadingDone();
    }

}

private class ItemUpload extends Thread{

    @Override
    public void run() {
        Log.i(TAG, "ItemUpload Thread started");
        isItemUploaded = true;
        if(!uploadingDone)
            uploadingDone();
    }
}

private class StoreUpload extends Thread{

    @Override
    public void run() {
        Log.i(TAG, "StoreUpload Thread started");
        isStoreUploaded = true;
        if(!uploadingDone)
            uploadingDone();
    }

}

private ListUpload listUpload;
private StoreUpload storeUpload;
private ItemUpload itemUpload;

public void startUpload(){

    listUpload = new ListUpload();
    listUpload.start();

    storeUpload = new StoreUpload();
    storeUpload.start();

    itemUpload = new ItemUpload();
    itemUpload.start();

}

谢谢。

Answer 1

略过标志并添加

listUpload.join();
storeUpload.join();
itemUpload.join();
// <BLOCK1>

在startUpload（）的末尾。每次调用join（）都会导致调用线程阻塞，直到给定的线程结束。

Answer 2

我修改了我的来源claesv提到。我发布了我的结果代码，以显示此Thread.join方法如何简化我的任务。希望会帮助别人。

private void uploadingDone(){

if( isItemUploaded && isListUploaded && isStoreUploaded){
    uploadingDone = true;
     //<BLOCK1>
    //TODO move to next screen
}else{
    Log.i(TAG, "uploadingDone: Failed");
    showFailureAlert();
}
}

// These flags are used to VALIDADTION success of uploading process. No need if you no need validation to move screen.

private boolean isListUploaded = false, isItemUploaded = false, isStoreUploaded =   false, uploadingDone = false;


private class ListUpload extends Thread{

@Override
public void run() {
    isListUploaded = true;
    Log.i(TAG, "ListUpload Thread started");
}

}

private class ItemUpload extends Thread{

@Override
public void run() {
    Log.i(TAG, "ItemUpload Thread started");
    isItemUploaded = true;
}
}

 private class StoreUpload extends Thread{

@Override
public void run() {
    Log.i(TAG, "StoreUpload Thread started");
    isStoreUploaded = true;
}

}

private ListUpload listUpload;
private StoreUpload storeUpload;
private ItemUpload itemUpload;

public void startUpload(){

listUpload = new ListUpload();
listUpload.start();

storeUpload = new StoreUpload();
storeUpload.start();

itemUpload = new ItemUpload();
itemUpload.start();

listUpload.join();
storeUpload.join();
itemUpload.join();

//Here comes the final block to execute after all threads finished
uploadingDone();

}

注意：不要在thread.start（）之后放置thread.join（）考虑一下：

t1.start();
t2.start();
t3.start();
t4.start();

t1.join();
t2.join();
t3.join();
t4.join();

Android Thread并发运行的线程在它们之间通知

2 个答案: