取消正在执行的 AsyncTask 的理想方法 [英] Ideal way to cancel an executing AsyncTask

问题描述

我正在使用 AsyncTask 在后台线程中运行远程音频文件提取和音频文件播放操作.Cancellable 进度条显示获取操作运行的时间.

I am running remote audio-file-fetching and audio file playback operations in a background thread using AsyncTask. A Cancellable progress bar is shown for the time the fetch operation runs.

我想在用户取消(决定反对)操作时取消/中止 AsyncTask 运行.处理这种情况的理想方法是什么?

I want to cancel/abort the AsyncTask run when the user cancels (decides against) the operation. What is the ideal way to handle such a case?

推荐答案

刚发现AlertDialogs的boolean cancel(...);我一直在用到处实际上什么都不做.太好了.
所以……

Just discovered that AlertDialogs's boolean cancel(...); I've been using everywhere actually does nothing. Great.
So...

public class MyTask extends AsyncTask<Void, Void, Void> {

    private volatile boolean running = true;
    private final ProgressDialog progressDialog;

    public MyTask(Context ctx) {
        progressDialog = gimmeOne(ctx);

        progressDialog.setCancelable(true);
        progressDialog.setOnCancelListener(new OnCancelListener() {
            @Override
            public void onCancel(DialogInterface dialog) {
                // actually could set running = false; right here, but I'll
                // stick to contract.
                cancel(true);
            }
        });

    }

    @Override
    protected void onPreExecute() {
        progressDialog.show();
    }

    @Override
    protected void onCancelled() {
        running = false;
    }

    @Override
    protected Void doInBackground(Void... params) {

        while (running) {
            // does the hard work
        }
        return null;
    }

    // ...

}

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