getting err when starting app

[Tony fig]

im getting an err ever time I try ruing the app. can some one tell what the err is...here is the err.

D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.tony.concerts_, PID: 2940
    java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
        at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
        at org.json.JSONTokener.nextValue(JSONTokener.java:94)
        at org.json.JSONObject.<init>(JSONObject.java:159)
        at org.json.JSONObject.<init>(JSONObject.java:176)
        at com.example.tony.concerts_.MainActivity$DownloadWeather.onPostExecute(MainActivity.java:161)
        at com.example.tony.concerts_.MainActivity$DownloadWeather.onPostExecute(MainActivity.java:144)
        at android.os.AsyncTask.finish(AsyncTask.java:695)
        at android.os.AsyncTask.access$600(AsyncTask.java:180)
        at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:712)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7037)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
I/Process: Sending signal. PID: 2940 SIG: 9
Process 2940 terminated.

[Tim Moores]

We don't know what "the app" is, but the error message is quite clear: a method is invoked on a null object reference. What object that is we can't say without seeing the code, but since the exact line number is given, it's easy for you to find out.

[Tony fig]

what is the line number?

[Tim Moores]

The line numbers are listed behind the class names, separated by a colon.

[Tony fig]

so the line is number is not list in the err i just listed?

[Tony fig]

isn't the line number 2940?

[Tim Moores]

2940 is the PID (process ID).

Look for the names of your classes. As I said, the line numbers are behind the class names, separated by a colon.

[Tony fig]

I don't know where the classes are. were do i find them?

[Dave Tolls]

In the stack trace there are these two lines, which I assume are referencing your code as they're the only classes I don't recognise:

at com.example.tony.concerts_.MainActivity$DownloadWeather.onPostExecute(MainActivity.java:161)
at com.example.tony.concerts_.MainActivity$DownloadWeather.onPostExecute(MainActivity.java:144)


So what is going on in that onPostExecute method in the MainActivity.DownloadWeather class?

[Tony fig]

Here is what I have between those two lines.

    class DownloadWeather extends AsyncTask < String, Void, String > {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            loader.setVisibility(View.VISIBLE);

        }
        protected String doInBackground(String...args) {
            String xml = Function.excuteGet("http://api.openweathermap.org/data/2.5/weather?q=" + args[0] +
                    "&units=metric&appid=" + OPEN_WEATHER_MAP_API);
            return xml;
        }

[Tim Moores]

I don't know where the classes are. were do i find them?

Does "com.example.tony.concerts_.MainActivity$DownloadWeather" not look like the name of one of your classes? I advise to familiarize yourself with such stack traces - you will see (and will have to analyze) a lot of them if you're serious about Android development.

What you posted is not line 161 (or line 144) of your code. As the stack trace shows, the error occurs in the onPostExecute method when a JSONObject is initialized. So make sure that line of code works with correct data. If you're unsure, print all the relevant data to the logcat (you know how to do that, right?) - before the line that causes the problem :-)

[Campbell Ritchie]

Please supply more details about the args array.

[Tim Moores]

One thing that looks wrong is that doInBackground looks like it receives XML, but onPostExecute apparently does something with JSON - is that the same data? If so, what kind is it?

[Tony fig]

I don't get an err if I run it on android 8.0 but on android 9.0 i get the err.

[Tim Moores]

I merged your stuff with the following thread. I hope that is okay by you.

[Tony fig]

I have this code for downloading the weather. it works on android 8.0 but wont work on android 9.0. can someone tell me why it wont work on android 9.0?


Here is the code.

  class DownloadWeather2 extends AsyncTask < String, Void, String > {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            loader.setVisibility(View.VISIBLE);

        }
        protected String doInBackground(String...args) {
            String xml = Function.excuteGet("http://api.openweathermap.org/data/2.5/weather?q=" + args[0] +
                    "&units=metric&appid=" + OPEN_WEATHER_MAP_API);
            return xml;
        }

        @Override
        protected void onPostExecute(String xml) {

            try {
                JSONObject json = new JSONObject(xml);
                if (json != null) {
                    JSONObject details = json.getJSONArray("weather").getJSONObject(0);
                    JSONObject main = json.getJSONObject("main");
                    // DateFormat df = DateFormat.getDateTimeInstance();

                    cityField2.setText(json.getString("name").toUpperCase(Locale.US) + ", " + json.getJSONObject("sys").getString("country"));
                   detailsField2.setText(details.getString("description").toUpperCase(Locale.US));
                    currentTemperatureField2.setText(String.format("%.2f", main.getDouble("temp")) + "°");
                    humidity_field2.setText("Humidity: " + main.getString("humidity") + "%");
                    pressure_field2.setText("Pressure: " + main.getString("pressure") + " hPa");
                    // updatedField.setText(df.format(new Date(json.getLong("dt") * 1000)));

                    int x = (int) main.getDouble("temp");
                    fernhight = (x*9/5)+32;
                    portugalf.setText(String.valueOf(fernhight + "°" ));
                    weatherIcon2.setText(Html.fromHtml(Function.setWeatherIcon(details.getInt("id"),
                            json.getJSONObject("sys").getLong("sunrise") * 1000,
                            json.getJSONObject("sys").getLong("sunset") * 1000)
                            ));

                    loader2.setVisibility(View.GONE);

                }
            } catch (JSONException e) {
                Toast.makeText(getApplicationContext(), "Error, Check City", Toast.LENGTH_SHORT).show();
            }


        }


    }

[Tim Moores]

So which one is line 161 of this code - I'm guessing line 18? Have you verified that what the code calls "xml" is in fact valid JSON? Maybe by printing it to the logcat? If not, start with that.

Also, you should print out the full stack trace in the catch block.

[Rob Spoor]

Tony fig wrote:

        at org.json.JSONObject.<init>(JSONObject.java:176)
        at com.example.tony.concerts_.MainActivity$DownloadWeather.onPostExecute(MainActivity.java:161)

Tony fig wrote:

        @Override
        protected void onPostExecute(String xml) {

            try {
                JSONObject json = new JSONObject(xml);

The org.json.JSONObject.<init> means the JSONObject constructor. That makes the above line the #1 suspect. Where does xml come from, and what is its actual value? Is the null check maybe done one line too early, and should it check xml instead?

[Tony fig]

here is teh logcat err

 

2019-08-15 20:43:00.005 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 20:43:00.005 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 20:43:00.117 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 20:43:00.117 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1

[Tim Moores]

That's not output from your app, but from android. Please reread what Rob and I wrote, and answer our questions.

[Tony fig]

I get no other err it just wont work on android 9.0.

[Tim Moores]

The NullPointerException you mentioned in the first post no longer happens? And still the app crashes?

[Tony fig]

Here is all the errs i get  these are the errs i get they just keep repeating down the page.

2019-08-15 18:50:18.795 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 56 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:50:20.722 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 56 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:50:21.740 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 60 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:50:22.717 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 58 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:50:23.701 6333-6333/com.example.tony.concerts_ I/chatty: uid=10068(u0_a68) com.example.tony.concerts_ identical 1 line
2019-08-15 18:50:27.638 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 56 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:50:29.545 6333-6333/com.example.tony.concerts_ I/chatty: uid=10068(u0_a68) com.example.tony.concerts_ identical 2 lines
2019-08-15 18:50:31.558 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 56 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:50:49.262 6333-6333/com.example.tony.concerts_ I/chatty: uid=10068(u0_a68) com.example.tony.concerts_ identical 1 line
2019-08-15 18:50:50.242 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 57 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:51:13.471 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 77 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:51:13.524 6333-6348/com.example.tony.concerts_ I/zygote: Background concurrent copying GC freed 20967(1260KB) AllocSpace objects, 8(160KB) LOS objects, 49% free, 1641KB/3MB, paused 6.444ms total 61.891ms
2019-08-15 18:51:14.656 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 70 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:52:04.877 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 74 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:52:04.931 6333-6348/com.example.tony.concerts_ I/zygote: Background concurrent copying GC freed 20914(1298KB) AllocSpace objects, 10(200KB) LOS objects, 50% free, 1533KB/2MB, paused 9.753ms total 65.039ms
2019-08-15 18:52:06.306 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 84 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:52:22.538 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 65 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:52:23.539 519-684/system_process D/WificondControl: Scan result ready event
2019-08-15 18:52:23.592 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 61 frames!  The application may be doing too much work on its main thread.

2019-08-15 18:52:55.423 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 74 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:52:55.475 6333-6348/com.example.tony.concerts_ I/zygote: Background concurrent copying GC freed 19784(1228KB) AllocSpace objects, 10(200KB) LOS objects, 49% free, 1562KB/3MB, paused 7.905ms total 68.246ms
2019-08-15 18:52:56.895 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 85 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:53:58.604 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 59 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:54:00.020 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:54:00.020 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:54:00.056 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:54:00.056 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:54:00.096 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:54:00.096 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:54:00.110 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:54:00.110 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:54:00.126 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:54:00.126 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:54:00.728 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 68 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:54:53.913 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 74 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:54:56.938 519-548/system_process E/BluetoothAdapter: Bluetooth binder is null
2019-08-15 18:54:56.948 519-548/system_process E/BatteryStatsService: modem info is invalid: ModemActivityInfo{ mTimestamp=0 mSleepTimeMs=0 mIdleTimeMs=0 mTxTimeMs[]=[0, 0, 0, 0, 0] mRxTimeMs=0 mEnergyUsed=0}
2019-08-15 18:54:56.953 519-548/system_process I/BatteryStatsImpl: Resetting battery stats: level=100 status=5 dischargeLevel=100 lowAmount=0 highAmount=0
2019-08-15 18:54:56.956 519-548/system_process E/BatteryStatsService: Power Hal not loaded
2019-08-15 18:54:57.191 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 98 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:54:58.649 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 87 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:54:58.837 519-519/system_process I/EntropyMixer: Writing entropy...
2019-08-15 18:54:59.000 519-548/system_process E/BluetoothAdapter: Bluetooth binder is null
2019-08-15 18:54:59.076 519-548/system_process E/BatteryStatsService: modem info is invalid: ModemActivityInfo{ mTimestamp=0 mSleepTimeMs=0 mIdleTimeMs=0 mTxTimeMs[]=[0, 0, 0, 0, 0] mRxTimeMs=0 mEnergyUsed=0}
2019-08-15 18:55:00.024 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:55:00.024 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:55:00.149 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:55:00.149 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:55:00.174 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:55:00.174 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:55:55.575 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 62 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:55:56.621 6333-6333/com.example.tony.concerts_ I/chatty: uid=10068(u0_a68) com.example.tony.concerts_ identical 1 line
2019-08-15 18:55:57.665 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 62 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:55:59.781 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 64 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:56:00.841 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:56:00.841 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:56:01.883 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 61 frames!  The application may be doing too much work on its main thread
2019-08-15 18:55:00.662 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 118 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:57:42.956 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 57 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:57:43.531 519-684/system_process D/WificondControl: Scan result ready event
2019-08-15 18:57:43.918 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 57 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:58:00.399 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 58 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:58:01.371 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 18:58:01.371 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 18:58:02.372 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 58 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:58:17.800 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 58 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:58:19.779 6333-6333/com.example.tony.concerts_ I/chatty: uid=10068(u0_a68) com.example.tony.concerts_ identical 2 lines
2019-08-15 18:58:20.764 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 58 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:58:48.079 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 57 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:58:50.016 6333-6333/com.example.tony.concerts_ I/chatty: uid=10068(u0_a68) com.example.tony.concerts_ identical 2 lines
2019-08-15 18:58:50.982 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 57 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:59:04.590 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 58 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:59:04.616 6333-6348/com.example.tony.concerts_ I/zygote: Background concurrent copying GC freed 22091(1364KB) AllocSpace objects, 9(180KB) LOS objects, 49% free, 1585KB/3MB, paused 5.840ms total 51.370ms
2019-08-15 18:59:05.538 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 55 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:59:35.185 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 56 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:59:36.137 6333-6333/com.example.tony.concerts_ I/chatty: uid=10068(u0_a68) com.example.tony.concerts_ identical 1 line
2019-08-15 18:59:37.087 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 56 frames!  The application may be doing too much work on its main thread.
2019-08-15 18:59:59.052 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 60 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:00.010 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 19:00:00.011 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 19:00:00.081 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 61 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:04.047 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 58 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:05.000 519-542/system_process E/memtrack: Couldn't load memtrack module
2019-08-15 19:00:05.000 519-542/system_process W/android.os.Debug: failed to get memory consumption info: -1
2019-08-15 19:00:05.080 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 61 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:23.134 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 96 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:23.664 519-1253/system_process D/WificondControl: Scan result ready event
2019-08-15 19:00:25.400 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 134 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:26.968 519-548/system_process E/BluetoothAdapter: Bluetooth binder is null
2019-08-15 19:00:27.031 519-548/system_process E/BatteryStatsService: modem info is invalid: ModemActivityInfo{ mTimestamp=0 mSleepTimeMs=0 mIdleTimeMs=0 mTxTimeMs[]=[0, 0, 0, 0, 0] mRxTimeMs=0 mEnergyUsed=0}
2019-08-15 19:00:27.031 519-548/system_process I/BatteryStatsImpl: Resetting battery stats: level=100 status=5 dischargeLevel=100 lowAmount=0 highAmount=0
2019-08-15 19:00:27.039 519-548/system_process E/BatteryStatsService: Power Hal not loaded
2019-08-15 19:00:27.474 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 123 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:28.520 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 62 frames!  The application may be doing too much work on its main thread.
2019-08-15 19:00:28.827 519-519/system_process I/EntropyMixer: Writing entropy...
2019-08-15 19:00:28.946 519-548/system_process E/BluetoothAdapter: Bluetooth binder is null
2019-08-15 19:00:28.959 519-548/system_process E/BatteryStatsService: modem info is invalid: ModemActivityInfo{ mTimestamp=0 mSleepTimeMs=0 mIdleTimeMs=0 mTxTimeMs[]=[0, 0, 0, 0, 0] mRxTimeMs=0 mEnergyUsed=0}
2019-08-15 19:00:29.653 6333-6333/com.example.tony.concerts_ I/Choreographer: Skipped 67 frames!  The application may be doing too much work on its main thread.

[Tim Moores]

So the app no longer crashes? But it does not do what you expect it to do? If so, TellTheDetails of what it does do, and at what point it deviates from what you expected it to do.

[Tony fig]

When I run the app I get those errs and than it crashes and its says this "08/18 07:15:40: Launching 'app' on samsung SM-G975W.
$ adb shell am start -n "com.example.tony.concerts_/com.example.tony.concerts_.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Waiting for process to come online...
Connected to process 2421 on device 'samsung-sm_g975w-R58M42AW06M'.
Process 2421 terminated."