Question

我写了这个帮手方法来从任何地方展示吐司。在我将它添加到我的帮助库集合之前，有人可以看一下并说它一切正常吗？

static void showToast(Context ctx, CharSequence msg) {

    Looper mainLooper = Looper.getMainLooper();
    Runnable r = new ToastOnUIThread(ctx, msg);

    boolean onUiThread;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        onUiThread = mainLooper.isCurrentThread();
    } else {
        onUiThread = Thread.currentThread() == mainLooper.getThread();
    }

    if (!onUiThread) {
        if (ctx instanceof Activity) {
            ((Activity) ctx).runOnUiThread(r);
        } else {
            Handler h = new Handler(mainLooper);
            h.post(r);
        }
    } else {
        r.run();
    }
}

这里，ToastOnUIThread类是：

private static class ToastOnUIThread implements Runnable {

    private Context ctx;
    private CharSequence msg;

    private ToastOnUIThread(Context ctx, CharSequence msg) {

        this.ctx = ctx;
        this.msg = msg;
    }

    public void run() {

        Toast.makeText(ctx, msg, Toast.LENGTH_SHORT).show();
    }
};

Answer 1

我还没有发现任何问题，但是Context是否是Activity的实例也许并不重要，因为：

public final void runOnUiThread(Runnable action) {
    if (Thread.currentThread() != mUiThread) {
        mHandler.post(action);
    } else {
        action.run();
    }
}

所以，你只需要它：

Handler h = new Handler(mainLooper);
h.post(r);

在任何情况下都显示Toast

1 个答案: