Question

所以我在一个单独的服务中使用OkHttp从twitter API获取数据。我一直试图警告用户没有互联网连接就无法加载推文。但是当我尝试这个时，应用程序崩溃。错误是：java.lang.RuntimeException：无法在未调用Looper.prepare（）的线程内创建处理程序。这是代码

 private void getTweets(final String topic) {
    final TwitterService twitterService = new TwitterService();
    twitterService.findTweets(topic, new Callback() {
        @Override
        public void onFailure(Request request, IOException e) {
            e.printStackTrace();
            Log.e("Traffic Activity", "Failed to make API call");
            Toast.makeText(getApplicationContext(), "Bigger fail", Toast.LENGTH_LONG).show();

        }

Answer 1

可能你是从错误的线程调用Toast.makeText。它需要从UI线程调用。试试这个

activity.runOnUiThread(new Runnable() {
    public void run() {
        Toast.makeText(activity, msg, Toast.LENGTH_SHORT).show();
    }
});

此处有更多信息Can't create handler inside thread that has not called Looper.prepare()

Answer 2

您正在从工作线程中调用它。您需要从主线程中调用Toast.makeText（）（以及处理UI的大多数其他函数）。您可以使用处理程序，例如

//在UI线程

中设置它

mHandler = new Handler(Looper.getMainLooper()) {
@Override
public void handleMessage(Message message) {
    // This is where you do your work in the UI thread.
    // Your worker tells you in the message what to do.
}

};

void workerThread() {
// And this is how you call it from the worker thread:
Message message = mHandler.obtainMessage(command, parameter);
message.sendToTarget();

}

如何在onfailure方法中祝酒

2 个答案: