Android Firebase Cloud Messaging from device to device

Question

我正在尝试将Firebase设备发送到设备推送通知，因此我有如下代码。

private void sendNotification(final String token) {
    new AsyncTask<Void,Void,Void>(){
        @Override
        protected Void doInBackground(Void... voids) {
            try {
                OkHttpClient client=new OkHttpClient();
                JSONObject json=new JSONObject();
                JSONObject dataJson=new JSONObject();
                dataJson.put("body","Hello, I am body");
                dataJson.put("title","I am title");
                json.put("notification",dataJson);
                json.put("to",token);
                RequestBody body=RequestBody.create(JSON,json.toString());
                Request request=new Request.Builder()
                        .header("Authorization","key="+LEGACY_SERVER_KEY)
                        .url("https://fcm.googleapis.com/fcm/send")
                        .post(body)
                        .build();
                Response response=client.newCall(request).execute();
                String finalResponse=response.body().string();
                //Toast.makeText(MainActivity.this, finalResponse, Toast.LENGTH_SHORT).show();
            }catch (Exception e){
                Toast.makeText(MainActivity.this, "Exception occured", Toast.LENGTH_SHORT).show();
            }
            return null;
        }
    }.execute();
}

这里的问题是通知未发送到其他设备。但是当我取消注释 Toast(尝试块的最后一行(时，通知将成功发送并立即显示应用程序停止工作。有人请帮忙。

当我取消注释时，Toast(尝试块的最后一行(通知将发送，但它说不幸的是应用程序停止了。日志猫是：

01-23 07:17:11.907 4694-4731/bhavana.apps.saveme E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
    Process: bhavana.apps.saveme, PID: 4694
    java.lang.RuntimeException: An error occurred while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:353)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:252)
        at java.util.concurrent.FutureTask.run(FutureTask.java:271)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
        at java.lang.Thread.run(Thread.java:764)
     Caused by: java.lang.RuntimeException: Can't toast on a thread that has not called Looper.prepare()
        at android.widget.Toast$TN.<init>(Toast.java:390)
        at android.widget.Toast.<init>(Toast.java:114)
        at android.widget.Toast.makeText(Toast.java:277)
        at android.widget.Toast.makeText(Toast.java:267)
        at bhavana.apps.saveme.MainActivity$6.doInBackground(MainActivity.java:199)
        at bhavana.apps.saveme.MainActivity$6.doInBackground(MainActivity.java:176)
        at android.os.AsyncTask$2.call(AsyncTask.java:333)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636) 
        at java.lang.Thread.run(Thread.java:764) 

Answer 1

只能在 UI 线程中显示 Toast。
删除此行或将其移至onPostExecute：

Toast.makeText(MainActivity.this, "Exception occured", Toast.LENGTH_SHORT).show();

Answer 2

Toast.makeText()需要在UI Thread中执行。尝试将其替换为：

new Handler(Looper.getMainLooper()).post(new Runnable() {
    @Override
    public void run() {
        Toast.makeText(MainActivity.this, "Exception occured", Toast.LENGTH_SHORT).show();
    }
});

或者，如果您只需要调试，则只需使用 Log：

android.util.Log.i("debug", "success msg: " + finalResponse);

您可以通过覆盖onPostExecute()来检查doInBackground()的状态

@Override
protected void onPostExecute(Boolean result) {
    android.util.Log.i("debug", "onPostExecute: " + result);
}

这假设onPostExecute()返回Boolean，因此：

@Override
protected Boolean doInBackground(Void... params) {
    ......
    // return true on success
    if (success) {
        return true;
    }
    return false;
}

类需要这样定义：

new AsyncTask<Void, Void, Boolean>(){

Answer 3

由以下原因引起：java.lang.Runtime异常：无法在线程上吐司 没有调用 Looper.prepare((

您应该使用 runOnUiThread .

在 UI 线程上运行指定的操作。如果当前线程是 UI 线程，然后立即执行操作。如果当前 线程不是 UI 线程，操作发布到事件队列 的 UI 线程。

runOnUiThread(new Runnable() {
      public void run() {
         Toast.makeText(MainActivity.this, "Exception occured", Toast.LENGTH_SHORT).show();
      }
 });