I was on my way of making a simple app that retrieves some list data from shared preferences and shows it on the screen. Long story short, the code to display the list is in a fragment 'InventoryFragment'. Inside that, I have a button, and I set an onClick so that an intent is sent to open another activity 'AddActivity'. That's where it crashes, at startActivity(intent).
It is a silly problem, but I can't find the solution. I tried with a simple 'TestActivity' (with just a textview showing up), and that gets shown, but not 'AddActivity'.
What is the error?
InventoryFragment:
package com.coffeetech.kittycatch;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.net.Uri;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.Type;
import java.util.ArrayList;
public class InventoryFragment extends Fragment {
public InventoryFragment() {
}
//GLOBAL VARIABLES
private ArrayList<Food> foods;
private FoodAdapter foodAdapter;
private ListView listView;
private FloatingActionButton floatingActionButton;
private View rootView;
private Food food; //FOR BUNDLE
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState){
loadData(); //loading the data into arraylist
if (getArguments()!=null){
food.name = getArguments().getString("name");
food.quantity=getArguments().getInt("quantity");
food.min_quantity=getArguments().getInt("quantity_min");
food.type=getArguments().getInt("type");
foods.add(food);
saveData();
}
//LOCATING THE FRAGMENT LAYOUT
rootView = inflater.inflate(R.layout.inventory_fragment, container, false);
//FOOD USAGE
//foods.add(new Food("Tomatoes", 0, 10, 2));
//SETTING ADAPTER FOR FOOD LIST
foodAdapter = new FoodAdapter(getActivity(),foods);
// SETTING LISTVIEW WITH ADAPTER
listView = rootView.findViewById(R.id.list_view);
listView.setAdapter(foodAdapter);
//setting up the Add button
floatingActionButton = rootView.findViewById(R.id.add_button);
floatingActionButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Go to ADD activity with no data, since new would be added
//Intent intent = new Intent(getActivity(),AddActivity.class);
//startActivity(intent);
Intent intent = new Intent(getActivity(),AddActivity.class);
startActivity(intent);
}
});
return rootView;
}
private void saveData(){
SharedPreferences sharedPreferences = getActivity().getSharedPreferences("shared preferences",Context.MODE_PRIVATE );
Editor editor = sharedPreferences.edit();
Gson gson = new Gson();
String json = gson.toJson(foods);
editor.putString("inventory",json);
editor.apply();
}
private void loadData(){
SharedPreferences sharedPreferences = getActivity().getSharedPreferences("shared preferences",Context.MODE_PRIVATE );
Gson gson = new Gson();
String json = sharedPreferences.getString("inventory",null);
Type type = new TypeToken<ArrayList<Food>>(){}.getType();
foods = gson.fromJson(json,type);
if (foods==null){
foods = new ArrayList<Food>();
}
}
@Override
public void onStop() {
saveData();
super.onStop();
}
}
Layout for the above fragment:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/inventory"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".InventoryFragment">
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/add_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
android:layout_margin="52dp"
android:background="#2196F3"
android:clickable="true"
android:src="@android:drawable/ic_menu_add" />
<ListView
android:id="@+id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="12dp"
android:layout_marginRight="12dp">
</ListView>
</FrameLayout>
AddActivity:
package com.coffeetech.kittycatch;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
public class AddActivity extends AppCompatActivity {
//GLOBAL VARIABLES
EditText item_name,quantity,quantity_min;
RadioGroup radio_group;
String name;
Button save;
int q,q_min,type;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_activity);
item_name = findViewById(R.id.name_add);
quantity=findViewById(R.id.quantity_add);
quantity_min=findViewById(R.id.min_quantity_add);
save=findViewById(R.id.save_button);
int id = radio_group.getCheckedRadioButtonId();
if (id == 1000008){
type=0;
}else{
type=1;
}
save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
name=item_name.getText().toString();
q=Integer.parseInt(String.valueOf(quantity.getText()));
q=Integer.parseInt(String.valueOf(quantity.getText()));
q_min=Integer.parseInt(String.valueOf(quantity_min.getText()));
//AT THIS POINT, name,q,q_min,type ARE READY TO BE BUNDLED
InventoryFragment inventoryFragment = new InventoryFragment();
Bundle args = new Bundle();
args.putString("name",name);
args.putInt("quantity_min",q_min);
args.putInt("quantity",q);
args.putInt("type",type);
inventoryFragment.setArguments(args);
getSupportFragmentManager().beginTransaction().replace(R.id.abcd,inventoryFragment).commit();
}
});
}
}
Layout for above:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/abcd"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="12sp"
android:layout_marginRight="12sp"
android:orientation="vertical"
tools:context=".AddActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Item name: " />
<EditText
android:id="@+id/name_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Minimum Quantity: " />
<EditText
android:id="@+id/min_quantity_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:ems="10"
android:inputType="numberDecimal" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Quantity (now): " />
<EditText
android:id="@+id/quantity_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:ems="10"
android:inputType="numberDecimal" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Type: " />
<RadioGroup
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1">
<RadioButton
android:id="@+id/discrete_button_add"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Discrete" />
<RadioButton
android:id="@+id/cont_button_add"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Continuous" />
</RadioGroup>
</LinearLayout>
<Button
android:id="@+id/save_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:text="SAVE" />
</LinearLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.coffeetech.kittycatch">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".AddActivity" />
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
logcat:
2020-04-05 02:59:54.359 18534-18534/? E/tech.kittycatc: Unknown bits set in runtime_flags: 0x28000
2020-04-05 02:59:54.501 18534-18563/com.coffeetech.kittycatch E/Perf: Fail to get file list com.coffeetech.kittycatch
2020-04-05 02:59:54.502 18534-18563/com.coffeetech.kittycatch E/Perf: getFolderSize() : Exception_1 = java.lang.NullPointerException: Attempt to get length of null array
2020-04-05 02:59:54.502 18534-18563/com.coffeetech.kittycatch E/Perf: Fail to get file list com.coffeetech.kittycatch
2020-04-05 02:59:54.502 18534-18563/com.coffeetech.kittycatch E/Perf: getFolderSize() : Exception_1 = java.lang.NullPointerException: Attempt to get length of null array
2020-04-05 02:59:54.503 18534-18563/com.coffeetech.kittycatch E/Perf: Fail to get file list oat
2020-04-05 02:59:54.504 18534-18563/com.coffeetech.kittycatch E/Perf: getFolderSize() : Exception_1 = java.lang.NullPointerException: Attempt to get length of null array
2020-04-05 03:00:04.424 18534-18534/com.coffeetech.kittycatch E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.coffeetech.kittycatch, PID: 18534
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.coffeetech.kittycatch/com.coffeetech.kittycatch.AddActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.RadioGroup.getCheckedRadioButtonId()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3497)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3636)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:100)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2222)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:228)
at android.app.ActivityThread.main(ActivityThread.java:7782)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:981)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.RadioGroup.getCheckedRadioButtonId()' on a null object reference
at com.coffeetech.kittycatch.AddActivity.onCreate(AddActivity.java:31)
at android.app.Activity.performCreate(Activity.java:7964)
at android.app.Activity.performCreate(Activity.java:7953)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3472)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3636)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:100)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2222)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:228)
at android.app.ActivityThread.main(ActivityThread.java:7782)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:981)
Thanks in advance to anyone who replies :)
