I have a method in a library I am creating for a series of apps I am doing. This method will display an input dialog for the user to input a string entry. I am writing this project for android using android studio, and I am writing it in Java.
Here is the Logcat:
2020-11-17 00:44:23.819 6758-6758/com.phoenixhosman.launcher E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.phoenixhosman.launcher, PID: 6758
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
at android.content.ContextWrapper.getResources(ContextWrapper.java:91)
at android.view.ContextThemeWrapper.getResourcesInternal(ContextThemeWrapper.java:127)
at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:121)
at android.content.Context.getString(Context.java:594)
at com.phoenixhosman.phoenixlib.ActivityPhoenixLib.InputDialog(ActivityPhoenixLib.java:97)
at com.phoenixhosman.launcher.ActivityHome.onClick(ActivityHome.java:151)
at android.view.View.performClick(View.java:6603)
at android.view.View.performClickInternal(View.java:6576)
at android.view.View.access$3100(View.java:780)
at android.view.View$PerformClick.run(View.java:26090)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6714)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:503)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:911)
Here in my ActivityHome.java file:
/*
The Phoenix Hospitality Management System
Launcher App Source Code
Main Activity Code File
Copyright (c) 2020 By Troy Marker Enterprises
All Rights Under Copyright Reserved
The code in this file was created for use with the Phoenix Hospitality Management System (PHMS).
Use of this code outside the PHMS is strictly prohibited.
*/
package com.phoenixhosman.launcher;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import androidx.annotation.NonNull;
import com.phoenixhosman.phoenixapi.*;
import com.phoenixhosman.phoenixlib.ProviderUser;
import com.phoenixhosman.phoenixlib.ActivityPhoenixLib;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.concurrent.atomic.AtomicInteger;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import static com.phoenixhosman.phoenixapi.ManagerSecurityApi.*;
/**
* This activity display links to the other apps in the Phoenix Hospitality
* system, and use authentication to only show those that the user has
* permission to use.
* @author Troy L. Marker
* @version 1.0.0
* @since 0.5.0
*/
public class ActivityHome extends Activity implements View.OnClickListener
{
private String strCoName;
private String strApiUrl;
private String strLockPass;
private EditText etUsername;
private EditText etPassword;
final private static int REQUEST_CODE_1 = 1;
final ActivityPhoenixLib Phoenix = new ActivityPhoenixLib();
/**
* This method will create the activity, read content to display, and show the main activity screen
* Used when the activity is (re)created.
* @param savedInstanceState current saved instance state
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
View decorView = getWindow().getDecorView();
decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN);
setContentView(R.layout.activity_home);
etUsername = findViewById(R.id.etUsername);
etPassword = findViewById(R.id.etPassword);
TextView tvWarning = findViewById(R.id.tvWarning);
Button btnLogon = findViewById(R.id.btnLogon);
Button btnLockPass = findViewById(R.id.btnLockPass);
btnLogon.setOnClickListener(this);
btnLockPass.setOnClickListener(this);
@SuppressLint("Recycle") Cursor cursor = getContentResolver().query(Uri.parse("content://com.phoenixhosman.installer.ProviderSettings/settings"), null, null, null, null, null);
assert cursor != null;
if(cursor.moveToFirst()) {
while(!cursor.isAfterLast()) {
strCoName = cursor.getString(cursor.getColumnIndex("coname"));
strApiUrl = cursor.getString(cursor.getColumnIndex("apiurl"));
strLockPass = cursor.getString(cursor.getColumnIndex("lockpass"));
cursor.moveToNext();
}
new ManagerSecurityApi(strApiUrl);
tvWarning.setText(getString(R.string.warning, rtrim(strCoName)));
} else {
Phoenix.Error(getApplicationContext(),getString(R.string.required), false);
}
}
/**
* Override of the onBackPress method from the parent class
* This disables the back button on the device.
*/
@Override
public void onBackPressed() {
Phoenix.Error(ActivityHome.this, getString(R.string.disabled, getString(R.string.back)),false);
}
/**
* This method overrides the parents click listner.
* @param v the view clicked.
*/
@Override
public void onClick(View v) {
Button button = (Button)v;
String buttonText = button.getText().toString();
if (buttonText.equals(getString(R.string.login))) {
if (etUsername.getText().toString().isEmpty() || etPassword.getText().toString().isEmpty()) {
Phoenix.Error(ActivityHome.this, getString(R.string.both_required,getString(R.string.username_password)), false);
} else {
Call<String> call = getInstance().getApi().login(etUsername.getText().toString(), etPassword.getText().toString());
call.enqueue(new Callback<String>() {
@Override
public void onResponse(@NonNull Call<String> call, @NonNull Response<String> response) {
String body = response.body();
try {
assert body != null;
JSONObject obj = new JSONObject(body);
if (obj.optBoolean("success")) {
etUsername.setText("");
etPassword.setText("");
etUsername.requestFocus();
getContentResolver().delete(ProviderUser.CONTENT_URI, null, null);
ContentValues values = new ContentValues();
values.put(ProviderUser.name, obj.optString("username"));
values.put(ProviderUser.grade, obj.optInt("grade"));
values.put(ProviderUser.gradename, obj.optString("gradename"));
values.put(ProviderUser.department, obj.optInt("department"));
values.put(ProviderUser.departmentname, obj.optString("departmentname"));
getContentResolver().insert(ProviderUser.CONTENT_URI, values);
Phoenix.Success(ActivityHome.this, obj.optString("message"), 5);
showApps(obj.optString("username"), obj.optInt("grade"), obj.optString("gradename"), obj.optInt("department"), obj.optString("departmentname"));
} else {
Phoenix.Error(getApplicationContext(), getString(R.string.user_not), false);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void onFailure(@NonNull Call<String> call, @NonNull Throwable t) {
}
});
}
} else if (buttonText.equals(getString(R.string.admin_access))) {
String LockPass = Phoenix.InputDialog(ActivityHome.this.getApplicationContext(), getString(R.string.input_prompt, getString(R.string.enter_lock_pass)));
if (LockPass.equals(strLockPass)) {
this.getPackageManager().clearPackagePreferredActivities(this.getPackageName());
finish();
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
} else {
throw new IllegalStateException(getString(R.string.unexpected) + v.getId());
}
}
/**
* This method will call the App Display Activity
*/
private void showApps(String username, Integer grade, String gradename, Integer department, String departmentname){
Intent intent = new Intent(ActivityHome.this.getApplicationContext(), ActivityApp.class);
intent.putExtra("username", username);
intent.putExtra("grade", String.valueOf(grade));
intent.putExtra("gradename", gradename);
intent.putExtra("department", String.valueOf(department));
intent.putExtra("departmentname", departmentname);
startActivityForResult(intent, REQUEST_CODE_1);
}
/**
* Function to trim whitespace from the end of a string.
* @param s the string to trim
* @return the trimmed string
*/
@NonNull
public static String rtrim(String s) {
AtomicInteger i;
i = new AtomicInteger(s.length() - 1);
while (i.get() >= 0 && Character.isWhitespace(s.charAt(i.get()))) {
i.getAndDecrement();
}
return s.substring(0, i.get() +1);
}
}
And finially, here is my ActivityPhoenixLib.java file:
package com.phoenixhosman.phoenixlib;
import android.app.Activity;
import android.content.Context;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import static android.view.View.inflate;
public class ActivityPhoenixLib extends Activity {
/**
* While not needed, this constructor makes calls to the member method of the class
* to clear errors in the editor.
*/
public ActivityPhoenixLib() {
Error(this, "", false);
Success(this,"",0);
String dummy = InputDialog(this, "");
if (dummy.equals("test")) {
}
}
/**
* This method displays a dialog box with an error message and a close button.
* @param strError the error message to display
*/
public void Error(Context context, @NonNull String strError, Boolean exit) {
if (strError.equals("")) {
return;
}
AlertDialog.Builder mBuilder = new AlertDialog.Builder(context);
View view = inflate(context, R.layout.dialog_error, null);
Button btnExit = view.findViewById(R.id.btnExitButton);
Button btnError = view.findViewById(R.id.btnErrorMessage);
btnError.setText(strError);
mBuilder.setView(view);
AlertDialog dialog = mBuilder.create();
dialog.setCanceledOnTouchOutside(false);
dialog.setCancelable(false);
dialog.show();
btnExit.setOnClickListener(v -> {
dialog.dismiss();
if (exit) System.exit(0);
});
}
/**
* This method displays a dialog box with a message and a close button.
* It also has an auto close function to auto close after a specified number of seconds.
* @param strMessage the message to display
*/
public void Success(Context context, @NonNull String strMessage, Integer autoclose) {
if (strMessage.equals("")) {
return;
}
AlertDialog.Builder mBuilder = new AlertDialog.Builder(context);
View view = inflate(context, R.layout.dialog_success, null);
Button btnExit = view.findViewById(R.id.btnButton);
Button btnError = view.findViewById(R.id.btnMessage);
btnError.setText(strMessage);
mBuilder.setView(view);
AlertDialog dialog = mBuilder.create();
dialog.setCanceledOnTouchOutside(false);
dialog.setCancelable(false);
dialog.show();
btnExit.setOnClickListener(v -> dialog.dismiss());
new Handler().postDelayed(dialog::dismiss, autoclose * 1000);
}
/**
* This method show an input box to get string input from the user.
* @param strPrompt - the dialog prompt
*/
public String InputDialog(Context context, String strPrompt) {
if (strPrompt.equals("")) {
return "";
}
AlertDialog.Builder mBuilder = new AlertDialog.Builder(context);
final String[] retval = new String[1];
View view = inflate(context, R.layout.dialog_input, null);
TextView txtPrompt = view.findViewById(R.id.txtPrompt);
EditText edtLockPass = view.findViewById(R.id.edtLockPass);
Button btnEnter = view.findViewById(R.id.btnEnter);
--> Line 97 <-- txtPrompt.setText(getString(R.string.input_prompt, strPrompt));
mBuilder.setView(view);
AlertDialog dialog = mBuilder.create();
dialog.setCanceledOnTouchOutside(false);
dialog.setCancelable(false);
dialog.show();
btnEnter.setOnClickListener(v -> {
if (edtLockPass.getText().toString().equals("")) {
retval[0] = "";
} else {
retval[0] = edtLockPass.getText().toString();
}
});
dialog.dismiss();
return retval[0];
}
}
I have tried several different things. I am going on the assumption that the context is not being passed to the InputDialog function, and I have tried different way of pass the context to the function: this. ActivityHome.this, getApplicationContext, and none of them seemed to work. Is there something I have nbot considered? Any help would be appreciated. Thanks.
Edit-In responce to one of the comments about my getString usage, on the page linked here my usage is documented, the second string is is the argument object for the formatting string.
Edit 2: I also tried to use a single parameter getSting on the line in question, and got the smae error.
