在所有可用的解决方案都失败后，我最终使用递归解决了问题。

代码:

//Recursive function, pass duration in seconds
public void showToast(int duration) {
    if (duration <= 0)
        return;

    Toast.makeText(this, "Hello, it's a toast", Toast.LENGTH_LONG).show();
    Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            showToast(duration-1);
        }
    }, 1000);
}

不，这里列出的大多数/所有黑客都不再适用于android 9。但有一个更好的解决方案:如果你的消息需要挂着，使用对话框。

(new AlertDialog.Builder(this)).setTitle("Sorry!")
.setMessage("Please let me know by posting a beta comment on the play store .")
.setPositiveButton("OK", null).create().show();

将吐司设置为以毫秒为单位的特定时间段:

public void toast(int millisec, String msg) {
    Handler handler = null;
    final Toast[] toasts = new Toast[1];
    for(int i = 0; i < millisec; i+=2000) {
        toasts[0] = Toast.makeText(this, msg, Toast.LENGTH_SHORT);
        toasts[0].show();
        if(handler == null) {
            handler = new Handler();
            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    toasts[0].cancel();
                }
            }, millisec);
        }
    }
}

用户不能自定义吐司的持续时间。因为NotificationManagerService的scheduleTimeoutLocked()函数没有使用字段duration。源代码如下。

private void scheduleTimeoutLocked(ToastRecord r, boolean immediate)
    {
        Message m = Message.obtain(mHandler, MESSAGE_TIMEOUT, r);
        long delay = immediate ? 0 : (r.duration == Toast.LENGTH_LONG ? LONG_DELAY : SHORT_DELAY);
        mHandler.removeCallbacksAndMessages(r);
        mHandler.sendMessageDelayed(m, delay);
    }

如果你深入挖掘android代码，你会发现这些行清楚地表明，我们不能改变Toast消息的持续时间。

 NotificationManagerService.scheduleTimeoutLocked() {
    ...
    long delay = immediate ? 0 : (r.duration == Toast.LENGTH_LONG ? LONG_DELAY : SHORT_DELAY);
    }

持续时间的默认值为

private static final int LONG_DELAY = 3500; // 3.5 seconds
private static final int SHORT_DELAY = 2000; // 2 seconds

为此，我编写了一个辅助类。你可以在github上看到代码:https://github.com/quiqueqs/Toast-Expander/blob/master/src/com/thirtymatches/toasted/ToastedActivity.java

这是你如何在5秒(或5000毫秒)内显示祝酒词:

Toast aToast = Toast.makeText(this, "Hello World", Toast.LENGTH_SHORT);
ToastExpander.showFor(aToast, 5000);