I run my android app and no app launches and gives errors in the log? How do I fix?

Question

I just got done one part of my code and went to launch the app and everything went fine. The build was successful and no issues were found. I then go to the emulator and the app doesn't launch and the log shows a lot of error.

Anyone know where I messed up and how I can fix it.Below is the errors from the log that I receive and I also pasted in the code that I was working on.

2019-05-07 13:06:14.358 22792-22792/com.example.drunktankfix E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.drunktankfix, PID: 22792
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.drunktankfix/com.example.drunktankfix.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(int)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(int)' on a null object reference
        at com.example.drunktankfix.MainActivity.onCreate(MainActivity.java:55)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
2019-05-07 13:06:16.368 22792-22792/com.example.drunktankfix I/Process: Sending signal. PID: 22792 SIG: 9

Also here is the code:

     package com.example.drunktankfix;


    import android.content.Intent;
    import android.content.SharedPreferences;
    import android.net.Uri;
    import android.os.Bundle;
    import android.preference.PreferenceManager;
    import android.support.annotation.NonNull;
    import android.support.design.widget.BottomNavigationView;
    import android.support.v4.app.Fragment;
    import android.support.v7.app.AppCompatActivity;
    import android.view.MenuItem;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;

    import com.example.drunktankfix.AppFragment;
    import com.example.drunktankfix.BlacklistFragment;
    import com.example.drunktankfix.HelpFragment;
    import com.example.drunktankfix.HomeFragment;

    //implement the interface OnNavigationItemSelectedListener in your       activity class
public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {


     Button Save;
     EditText edt1, edt2, edt3;
     int in;
     Float fl;
     String st;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //loading the default fragment
        loadFragment(new HomeFragment());

        //getting bottom navigation view and attaching the listener
        BottomNavigationView navigation = findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(this);

        Save = (Button) findViewById(R.id.BtnSave);
        edt1 = (EditText) findViewById(R.id.editText1);
        edt2 = (EditText) findViewById(R.id.editText2);
        edt3 = (EditText) findViewById(R.id.editText3);

        // to Retrieve the Data from the SharedPref

            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
            int in1= prefs.getInt("in",0);
            edt1.setText(in1);

            float fl1 = prefs.getFloat("fl", 0);
            edt2.setText(""+fl1);

            String st1 = prefs.getString("st","");
            edt3.setText(st1);


        Save.setOnClickListener (new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                in = Integer.parseInt(edt1.getText().toString());
                fl = Float.parseFloat(edt2.getText().toString());
                st = edt3.getText().toString();

                // To save the data that is entered
                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(MainActivity.this);
                SharedPreferences.Editor editor = prefs.edit();

                editor.putInt("in", in);
                editor.putFloat("fl", fl);
                editor.putString("st", st);
                editor.apply();
            }
        });
    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        Fragment fragment = null;

        switch (item.getItemId()) {
            case R.id.navigation_home:
                fragment = new HomeFragment();
                break;

            case R.id.navigation_Apps:
                fragment = new AppFragment();
                break;

            case R.id.navigation_Blacklist:
                fragment = new BlacklistFragment();
                break;

            case R.id.navigation_Help:
                fragment = new HelpFragment();
                break;
        }

        return loadFragment(fragment);
    }

    private boolean loadFragment(Fragment fragment) {
        //switching fragment
        if (fragment != null) {
            getSupportFragmentManager()
                    .beginTransaction()
                    .replace(R.id.fragment_container, fragment)
                    .commit();
            return true;
        }
        return false;
    }

}

I think I added the code. It is kind of messed up format but that is all the code. — adilisi, May 07 '19 at 17:52

Ramesh Yankati · Answer 1 · 2019-05-08T08:08:10.177

0

I am not sure how are you getting Nullpointer Exception But from the I code, I see any issue with your here.

editText.setText(Integer Value)

You are setting integer value to Edit text, So that in turn tries to get String resource based on the integer which you set to EditText.That should throw Resource not found Exception not NPE.

edited May 08 '19 at 08:08

answered May 07 '19 at 17:45

Ramesh Yankati

1,197
9
13

how would i do init findviewbyid? I have three edittext im my xml so would i need editybox? – adilisi May 07 '19 at 19:54

score 0 · Answer 2 · answered May 07 '19 at 18:01

0

You can not enter int value inside the edit text . Try to make it string.

edt1.setText(in1+"");

answered May 07 '19 at 18:01

Ajay Kumar Sharma

74
6

I made this change and still have the same error. – adilisi May 07 '19 at 18:41
Check the value of in1 inside the log.e – Ajay Kumar Sharma May 07 '19 at 19:22
How would I check the value inside the log? – adilisi May 07 '19 at 20:10
int in1= prefs.getInt("in",0); Log.e("tag",in1.toSting());. If it give error means you did not get any value from prefer – Ajay Kumar Sharma May 07 '19 at 20:12

score 0 · Answer 3 · answered May 07 '19 at 18:06

0

To set the integer propertly do the following:

edt1.setText("" + integer);

or better solution:

edt1.setText(String.valueOf(integer));

answered May 07 '19 at 18:06

mohammadReza Abiri

1,759
1
9
20

I made this change and still the same errors. i have changed code to be edt1.setText("" + in1); – adilisi May 07 '19 at 18:37
I tested your code but did not get an error! – mohammadReza Abiri May 07 '19 at 19:23
1

Should the code be edt1.setText(String.valueOf(integer)); or edt1.setText("" + in1); – adilisi May 07 '19 at 19:33

I run my android app and no app launches and gives errors in the log? How do I fix?

3 Answers3