Lesson 5

app/src/main/AndroidManifest.xml

@@ -13,14 +13,15 @@
         <activity android:name=".Lesson1Activity" />
         <activity android:name=".Lesson2Activity" />
         <activity android:name=".Lesson3Activity" />
-        <activity android:name=".Lesson4Activity">
+        <activity android:name=".Lesson4Activity" />
+        <activity android:name=".Lesson4SubActivity" />
+        <activity android:name=".Lesson5Activity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-        <activity android:name=".Lesson4SubActivity" />
     </application>
 
 </manifest>

app/src/main/java/com/example/Lesson5Activity.java

@@ -0,0 +1,44 @@
+package com.example;
+
+import androidx.annotation.NonNull;
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.os.Bundle;
+import android.widget.Button;
+import android.widget.TextView;
+
+import com.example.dialog.MyDialogFragment;
+
+/**
+ * ダイアログの作り方についてレッスン。
+ */
+public class Lesson5Activity extends AppCompatActivity implements MyDialogFragment.Callback {
+
+    private TextView mTextView;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_lesson5);
+
+        mTextView = findViewById(R.id.lesson5_text_view);
+        Button button = findViewById(R.id.lesson5_button);
+
+        button.setOnClickListener((l) -> onClick());
+    }
+
+    private void onClick() {
+        MyDialogFragment dialog = new MyDialogFragment();
+        dialog.show(getSupportFragmentManager(), MyDialogFragment.class.getSimpleName());
+    }
+
+    @Override
+    public void onMyDialogSucceeded(@NonNull String successText) {
+        mTextView.setText(successText);
+    }
+
+    @Override
+    public void onMyDialogCancelled(@NonNull String cancelText) {
+        mTextView.setText(cancelText);
+    }
+}

app/src/main/java/com/example/dialog/MyDialogFragment.java

@@ -0,0 +1,59 @@
+package com.example.dialog;
+
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.os.Bundle;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.DialogFragment;
+
+public class MyDialogFragment extends DialogFragment {
+    private Callback mCallback;
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
+        builder.setMessage("Are you happy?")
+                .setPositiveButton("yes", new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        mCallback.onMyDialogSucceeded("YES");
+                    }
+                })
+                .setNegativeButton("no", new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        mCallback.onMyDialogCancelled("NO");
+                    }
+                });
+        return builder.create();
+    }
+
+    @Override
+    public void onAttach(@NonNull Context context) {
+        super.onAttach(context);
+        Object callback = getParentFragment();
+        if (callback == null) {
+            callback = getActivity();
+            if (!(callback instanceof Callback)) {
+                throw new IllegalStateException();
+            }
+        }
+        mCallback = (Callback) callback;
+    }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        mCallback = null;
+    }
+
+    public interface Callback {
+        void onMyDialogSucceeded(@NonNull String successText);
+        void onMyDialogCancelled(@NonNull String cancelText);
+    }
+}

app/src/main/res/layout/activity_lesson5.xml

@@ -0,0 +1,29 @@
+<?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=".Lesson5Activity">
+
+    <TextView
+        android:id="@+id/lesson5_text_view"
+        android:layout_width="59dp"
+        android:layout_height="20dp"
+        android:text="TextView"
+        app:layout_constraintBottom_toTopOf="@+id/lesson5_button"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="0.39" />
+
+    <Button
+        android:id="@+id/lesson5_button"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Button"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/lesson5_text_view" />
+</androidx.constraintlayout.widget.ConstraintLayout>