Start new Activity from Dialog-CodePudding

I try to open a new Activity after pressing OK Button but it doesn't work. Here is my code:

public class NameOfNewList extends AppCompatDialogFragment {

Context mActivity;

@NonNull
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
    
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    
    LayoutInflater layoutInflater = requireActivity().getLayoutInflater();

    mActivity = getContext();

    builder.setTitle("Nowa lista")
            .setView(layoutInflater.inflate(R.layout.activity_new_list_dialog, null))
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            })
            .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    startNewList();
                }
            });

    return builder.create();
}

public void startNewList() {
    Intent intent = new Intent(mActivity, NewList.class);
    startActivity(intent);
}

}

I've tried to find what is the problem but there was no answers to my question.

CodePudding user response：

You just need to add context

public void startNewList() {
    Intent intent = new Intent(mActivity, NewList.class);
    mActivity.startActivity(intent);
}

CodePudding user response：

I used your code to create a demo, it worked fine. You can check my code as below.

I tested on emulator Android 10

The main Activity:

public class MainActivity extends AppCompatActivity {

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

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startDialogFragment();
            }
        });
    }

    private void startDialogFragment() {
        new NameOfNewList().show(getSupportFragmentManager(), NameOfNewList.TAG);
    }

}

The main xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@ id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

The class NameOfNewList

public class NameOfNewList extends AppCompatDialogFragment {
    Context mActivity;

    public static String TAG = "NameOfNewList";

    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {

        AlertDialog.Builder builder = new AlertDialog.Builder(getContext());

        LayoutInflater layoutInflater = requireActivity().getLayoutInflater();

        mActivity = getContext();

        builder.setTitle("Nowa lista")
                .setView(layoutInflater.inflate(R.layout.activity_new_list_dialog, null))
                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                    }
                })
                .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        startNewList();
                    }
                });

        return builder.create();
    }

    public void startNewList() {
        Intent intent = new Intent(mActivity, NewList.class);
        startActivity(intent);
    }
}

The layout file activity_new_list_dialog

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".dialog.NewList">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TANCOLO" />

</LinearLayout>

The class NewList

public class NewList extends AppCompatActivity {

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

The file activity_new_list_class just contains one TextView

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".dialog.NewList">

    <TextView
        android:id="@ id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World 1111!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

The manifest file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.teststackoverflow">

    <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/Theme.TestStackoverflow">
        <activity android:name=".dialog.NewList"></activity>
        <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>

Regards the crash or sth. like that, you can check the logcat on Tab Run or Tab Logcat in the bottom of Android Studio.