Kotlinへ入門

React Nativeは基礎は終わったが、やはり、VR/ARのアプリを作成したりするには、

Androidプログラミングが必要とのことであり、やはり、Metaでも、Java→Kotlinの流れであるとのことでもあり、Kotlinに入門することとします。

 

そういえば、今のパソコンにはAndroid Studio入っていなかったのでそれを入れるところからかと思う。

 

AS Room編④　～Roomを使って、登録したデータを別のAcitivityに表示する～

EditTextに、名前を入力し、登録ボタンを押すとデータベースに登録される。

一覧表示ボタンを押すと、別のActivityでデータ一覧を確認できる。上下にスクロールできるようにしている。

EditTextに、データにある名前を入力し、削除ボタンを押すとデータベースから、そのデータが削除される。

 

MainActivity.java

package com.example.room5;

import androidx.appcompat.app.AppCompatActivity;
import androidx.room.Dao;

import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.google.android.material.snackbar.Snackbar;

import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    static AppDatabase db;

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

        TextView showData = findViewById(R.id.showData);

        Button registerBtn = findViewById(R.id.registerBtn);
        db = AppDatabaseSingleton.getInstance(getApplicationContext());
        registerBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new Thread(new Runnable(){

                    @Override
                    public void run() {
                        // 本質的な処理
                        UserDao userDao = db.userDao();
                        EditText editName = findViewById(R.id.editName);
                        userDao.insert(new User(editName.getText().toString()));
                    }
                }).start();

                Snackbar.make(MainActivity.this,view,"1件のデータが登録されました。",Snackbar.LENGTH_LONG).show();

            }
        });


        Button deleteBtn = findViewById(R.id.deleteBtn);
        deleteBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new Thread(new Runnable(){

                    @Override
                    public void run() {
                        // 本質的な処理
                        UserDao userDao = db.userDao();
                        EditText editName = findViewById(R.id.editName);
                        List<User> filterList = userDao.selectByUserName(editName.getText().toString());
                        for(int i=0;i<filterList.size();i++){
                            userDao.delete(filterList.get(i));
                        }
                    }
                }).start();

                Snackbar.make(MainActivity.this,view,"1件のデータが削除されました。",Snackbar.LENGTH_LONG).show();

            }
        });

        Button displayBtn = findViewById(R.id.displayBtn);
        displayBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(MainActivity.this,SecondActivity.class));
            }
        });

    }

}

SecondActivity.java

package com.example.room5;

import static com.example.room5.MainActivity.db;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class SecondActivity extends AppCompatActivity {


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

        TextView secondView = findViewById(R.id.secondView);

        //Handler
        Handler handler = new Handler(){
            public void handleMessage(Message msg){
                StringBuilder recievedStrBld =(StringBuilder) msg.obj;
                secondView.setText(recievedStrBld.toString());
            }

        };


        new Thread(new Runnable(){
            @Override
            public void run() {
                // 本質的な処理
                UserDao userDao = db.userDao();
                List<User> atList = userDao.getAll();
                StringBuilder sb = new StringBuilder();
                for(User user:atList){
                    sb.append(user.getName()).append("\n");
                }

                Message msg = new Message();
                msg.obj = sb;

                handler.sendMessage(msg);
            }
        }).start();
    }
}

activity_main.xml

<?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=".MainActivity"
    android:gravity="center_horizontal"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="名前："/>
    <EditText
        android:id="@+id/editName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    <Button
        android:id="@+id/registerBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="登録"/>
    <Button
        android:id="@+id/deleteBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="削除"/>
    <TextView
        android:id="@+id/showData"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <Button
        android:id="@+id/displayBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="一覧表示"/>

</LinearLayout>

activity_second.xml

<?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=".SecondActivity">

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:id="@+id/secondView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="40sp"/>
    </ScrollView>
</LinearLayout>

AppDatabase.java

package com.example.room5;

import androidx.room.Database;
import androidx.room.RoomDatabase;

@Database(entities = {User.class},version = 1,exportSchema = false)
public abstract class AppDatabase extends RoomDatabase {
    public abstract UserDao userDao();
}

AppDatabaseSingleton.java

package com.example.room5;

import android.content.Context;

import androidx.room.Room;

public class AppDatabaseSingleton {
    private static AppDatabase instance = null;

    static AppDatabase getInstance(Context context){
        instance = Room.databaseBuilder(context,AppDatabase.class,"dtabase-app").build();
        return instance;
    }
}

User.java

package com.example.room5;

import androidx.annotation.NonNull;
import androidx.room.ColumnInfo;
import androidx.room.Entity;
import androidx.room.PrimaryKey;

@Entity(tableName ="users")
public class User {
    @PrimaryKey(autoGenerate = true)
    @NonNull
    @ColumnInfo(name = "id")
    private int id;

    @ColumnInfo(name = "name")
    private String name;

    public User(String name) {
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

UserDao（インターフェース）

package com.example.room5;

import androidx.room.Dao;
import androidx.room.Delete;
import androidx.room.Insert;
import androidx.room.Query;

import java.util.List;

@Dao
public interface UserDao {
    @Insert
    void insertAll(User... users);

    @Insert
    void insert(User user);

    @Delete
    void delete(User user);

    @Query("SELECT * FROM users")
    List<User> getAll();

    @Query("SELECT * FROM users where name IN(:username)")
    List<User> selectByUserName(String username);
}

 

 

カウントダウンタイマーをつくる⑥try3の解答編

MainActivity.java

package com.example.intervaltimerdemo4;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements TimePickerDialogFragment.TimePickerDialogFragmentListener{

    private int start_time;
    private int START_TIME;
    Button nextBtn;
    Button configBtn;

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

        configBtn = findViewById(R.id.configBtn);
        nextBtn = findViewById(R.id.nextBtn);

        configBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                TimePickerDialogFragment timePickerDialogFragment = new TimePickerDialogFragment();
                timePickerDialogFragment.show(getSupportFragmentManager(),"TimePicker");
            }
        });

        nextBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this,FirstActivity.class);
                intent.putExtra("START_TIME",START_TIME);
                startActivity(intent);
            }
        });

    }

    public void onClickButton(int hour,int minute) {
        TextView textView = findViewById(R.id.textView);
        String hourStr = String.valueOf(hour);
        String minuteStr;
        if(minute<10){
            minuteStr = "0"+String.valueOf(minute);
        }else{
            minuteStr = String.valueOf(minute);
        }
        String timeStr = hourStr + ":" + minuteStr;
        textView.setText(timeStr);
        START_TIME = minute*60000 + hour*60*60000;
    }
}

activity_main.xml

<?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"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"/>

    <Button
        android:id="@+id/configBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="設定"/>

    <Button
        android:id="@+id/nextBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="次へ"/>

</LinearLayout>

FirstActivity.java

package com.example.intervaltimerdemo4;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class FirstActivity extends AppCompatActivity {
    private int START_TIME;
    TextView text_countdown;
    Button button_start;
    Button button_pause;
    Button button_reset;

    private boolean mTimerRunning;

    CountDownTimer mCountDownTimer;
    private long mTimeLeft;

    private MediaPlayer myMediaPlayer;

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

        Intent intent = getIntent();
        START_TIME = intent.getIntExtra("START_TIME",0);
        mTimeLeft = START_TIME;

        text_countdown = findViewById(R.id.text_view_countdown);
        int hours = (int)(mTimeLeft/1000)/60/60;
        int minutes = (int)(mTimeLeft/1000)/60;
        int seconds = (int)(mTimeLeft/1000)%60;
        String timerLeftFormatted = String.format(Locale.getDefault(), "%02d:%02d:%02d",hours,minutes, seconds);
        text_countdown.setText(timerLeftFormatted);
        button_start = findViewById(R.id.button_start);
        button_pause = findViewById(R.id.button_pause);
        button_reset = findViewById(R.id.button_reset);

        button_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
              if(text_countdown.getText().toString().equals("00:00")){
                  Toast.makeText(FirstActivity.this,"押しても音は出ません",Toast.LENGTH_SHORT).show();
                }else{
                    if(mTimerRunning == true){
                        Toast.makeText(FirstActivity.this,"カウントダウン中は押せません",Toast.LENGTH_SHORT).show();
                    }else {
                        startTimer();
                    }
                }

            }
        });

        button_pause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(mTimerRunning ==true){
                    pauseTimer();
                }else{
                    Toast.makeText(FirstActivity.this,"カウントダウン停止中なので押せません",Toast.LENGTH_SHORT).show();
                }

            }
        });

        button_reset.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(mTimerRunning == true){
                    Toast.makeText(FirstActivity.this,"カウントダウン中はリセットできません",Toast.LENGTH_SHORT).show();
                }else{
                    resetTimer();
                }

            }
        });
    }

    private void startTimer(){
        mCountDownTimer = (CountDownTimer) new MainCountDownTimer(mTimeLeft,1000);
        mCountDownTimer.start();
        mTimerRunning = true;
    }

    private void snoozeTimer(){
        mCountDownTimer = (CountDownTimer) new MainCountDownTimer(mTimeLeft,1000);
        mCountDownTimer.start();
        mTimerRunning = true;
    }

    public class MainCountDownTimer extends CountDownTimer{

        public MainCountDownTimer(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        @Override
        public void onTick(long TimeUntilFinished) {
            mTimeLeft = TimeUntilFinished;
            updateCountDownText();
        }

        @Override
        public void onFinish() {

            Toast.makeText(FirstActivity.this,"設定した時間が経過しました",Toast.LENGTH_LONG).show();

            myMediaPlayer = MediaPlayer.create(FirstActivity.this,R.raw.alarmdemo);
            try {
                myMediaPlayer.prepare();
            } catch (Exception e) {
                Log.v(null,e.toString());
            }
            myMediaPlayer.start();

            if(mTimerRunning == true){
                    mTimeLeft = 60000;
                    mTimerRunning = false;
                    updateCountDownText();
                    snoozeTimer();
            }else{
            }
        }
    }

    private void pauseTimer(){
        mCountDownTimer.cancel();
        mTimerRunning = false;
    }

    private void resetTimer(){
        mTimeLeft = START_TIME;
        mTimerRunning = false;
        updateCountDownText();
    }

    private void updateCountDownText(){
        int hours = (int)(mTimeLeft/1000)/60/60;
        int minutes = (int)(mTimeLeft/1000)/60;
        int seconds = (int)(mTimeLeft/1000)%60;
        String timerLeftFormatted = String.format(Locale.getDefault(), "%02d:%02d:%02d",hours,minutes, seconds);
        text_countdown.setText(timerLeftFormatted);
    }
}

activity_first.java

<?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"
    android:gravity="center_horizontal"
    android:orientation="vertical"
    tools:context=".FirstActivity">

    <TextView
        android:id="@+id/text_view_countdown"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="00:00:00"
        android:textSize="50sp"
        android:layout_marginTop="160sp"/>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <Button
            android:id="@+id/button_start"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="スタート"
            android:layout_marginTop="30sp"
            android:layout_marginRight="20sp"/>

        <Button
            android:id="@+id/button_pause"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="ストップ"
            android:layout_marginTop="30sp"
            android:layout_marginRight="20sp"  />

        <Button
            android:id="@+id/button_reset"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="リセット"
            android:layout_marginTop="30sp"/>
    </LinearLayout>

</LinearLayout>

TimePickerDialogFragment.java

package com.example.intervaltimerdemo4;

import android.app.AlertDialog;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.TimePickerDialog;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.widget.DatePicker;
import android.widget.TimePicker;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.DialogFragment;

import java.time.LocalDate;

public class TimePickerDialogFragment extends DialogFragment implements TimePickerDialog.OnTimeSetListener{

    @Override
    public void onTimeSet(TimePicker timePicker, int hour, int minute) {

        if (listener != null) {
            listener.onClickButton(hour,minute);
        }
    }

    public interface TimePickerDialogFragmentListener{
        void onClickButton(int hour,int minute);
    }

    private TimePickerDialogFragmentListener listener;

    public void onAttach(@NonNull Context context) {

        super.onAttach(context);

        if(context instanceof TimePickerDialogFragmentListener){
            listener = (TimePickerDialogFragmentListener) context;
        }
    }
    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState){
        int hour = 0;
        int minute = 0;


        Dialog timePickerDialog = new TimePickerDialog(getActivity(),android.R.style.Theme_Black,this,hour,minute,true);
        return timePickerDialog;
    }
}

 

 

 

カウントダウンタイマーをつくる⑥ try2の解答

 

GitHubに挙げたかったのですが、現在ノートパソコンでは、Bad credentialと出てしまい上げることができないので、貼り付けておきます。

 

MainActivity.java

package com.example.intervaltimerdemo4;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements TimePickerDialogFragment.TimePickerDialogFragmentListener{

    private int start_time;
    private int START_TIME;
    Button nextBtn;
    Button configBtn;

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

        configBtn = findViewById(R.id.configBtn);
        nextBtn = findViewById(R.id.nextBtn);

        configBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                TimePickerDialogFragment timePickerDialogFragment = new TimePickerDialogFragment();
                timePickerDialogFragment.show(getSupportFragmentManager(),"TimePicker");
            }
        });

        nextBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this,FirstActivity.class);
                intent.putExtra("START_TIME",START_TIME);
                startActivity(intent);
            }
        });

    }

    public void onClickButton(int hour,int minute) {
        TextView textView = findViewById(R.id.textView);
        String hourStr = String.valueOf(hour);
        String minuteStr;
        if(minute<10){
            minuteStr = "0"+String.valueOf(minute);
        }else{
            minuteStr = String.valueOf(minute);
        }
        String timeStr = hourStr + ":" + minuteStr;
        textView.setText(timeStr);
        START_TIME = minute*60000 + hour*60*60000;
    }
}

activity_main.xml

<?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"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"/>

    <Button
        android:id="@+id/configBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="設定"/>

    <Button
        android:id="@+id/nextBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="次へ"/>

</LinearLayout>

FirstActivity.java

package com.example.intervaltimerdemo4;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Locale;

public class FirstActivity extends AppCompatActivity {
    private int START_TIME;
    TextView text_countdown;
    Button button_start;
    Button button_pause;
    Button button_reset;

    private boolean mTimerRunning;

    CountDownTimer mCountDownTimer;
    private long mTimeLeft;

    private MediaPlayer myMediaPlayer;

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

        Intent intent = getIntent();
        START_TIME = intent.getIntExtra("START_TIME",0);
        mTimeLeft = START_TIME;

        text_countdown = findViewById(R.id.text_view_countdown);
        SimpleDateFormat sdf = new SimpleDateFormat("hh:mm:ss",Locale.US);
        text_countdown.setText(sdf.format(mTimeLeft));
        button_start = findViewById(R.id.button_start);
        button_pause = findViewById(R.id.button_pause);
        button_reset = findViewById(R.id.button_reset);

        button_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
              if(text_countdown.getText().toString().equals("00:00")){
                  Toast.makeText(FirstActivity.this,"押しても音は出ません",Toast.LENGTH_SHORT).show();
                }else{
                    if(mTimerRunning == true){
                        Toast.makeText(FirstActivity.this,"カウントダウン中は押せません",Toast.LENGTH_SHORT).show();
                    }else {
                        startTimer();
                    }
                }

            }
        });

        button_pause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(mTimerRunning ==true){
                    pauseTimer();
                }else{
                    Toast.makeText(FirstActivity.this,"カウントダウン停止中なので押せません",Toast.LENGTH_SHORT).show();
                }

            }
        });

        button_reset.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(mTimerRunning == true){
                    Toast.makeText(FirstActivity.this,"カウントダウン中はリセットできません",Toast.LENGTH_SHORT).show();
                }else{
                    resetTimer();
                }

            }
        });
    }

    private void startTimer(){
        mCountDownTimer = (CountDownTimer) new MainCountDownTimer(mTimeLeft,1000);
        mCountDownTimer.start();
        mTimerRunning = true;
    }

    private void snoozeTimer(){
        mCountDownTimer = (CountDownTimer) new MainCountDownTimer(mTimeLeft,1000);
        mCountDownTimer.start();
        mTimerRunning = true;
    }

    public class MainCountDownTimer extends CountDownTimer{

        public MainCountDownTimer(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        @Override
        public void onTick(long TimeUntilFinished) {
            mTimeLeft = TimeUntilFinished;
            updateCountDownText();
        }

        @Override
        public void onFinish() {

            Toast.makeText(FirstActivity.this,"設定した時間が経過しました",Toast.LENGTH_LONG).show();

            myMediaPlayer = MediaPlayer.create(FirstActivity.this,R.raw.alarmdemo);
            try {
                myMediaPlayer.prepare();
            } catch (Exception e) {
                Log.v(null,e.toString());
            }
            myMediaPlayer.start();

            if(mTimerRunning == true){
                    mTimeLeft = START_TIME;
                    mTimerRunning = false;
                    updateCountDownText();
                    snoozeTimer();
            }else{
            }
        }
    }

    private void pauseTimer(){
        mCountDownTimer.cancel();
        mTimerRunning = false;
    }

    private void resetTimer(){
        mTimeLeft = START_TIME;
        mTimerRunning = false;
        updateCountDownText();
    }

    private void updateCountDownText(){
        int minutes = (int)(mTimeLeft/1000)/60;
        int seconds = (int)(mTimeLeft/1000)%60;
        String timerLeftFormatted = String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds);
        text_countdown.setText(timerLeftFormatted);
    }
}

activity_first.xml

<?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"
    android:gravity="center_horizontal"
    android:orientation="vertical"
    tools:context=".FirstActivity">

    <TextView
        android:id="@+id/text_view_countdown"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="00:00"
        android:textSize="50sp"
        android:layout_marginTop="160sp"/>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <Button
            android:id="@+id/button_start"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="スタート"
            android:layout_marginTop="30sp"
            android:layout_marginRight="20sp"/>

        <Button
            android:id="@+id/button_pause"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="ストップ"
            android:layout_marginTop="30sp"
            android:layout_marginRight="20sp"  />

        <Button
            android:id="@+id/button_reset"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="リセット"
            android:layout_marginTop="30sp"/>
    </LinearLayout>

</LinearLayout>

TimePickerDialogFragment.java

package com.example.intervaltimerdemo4;

import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.TimePickerDialog;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.widget.DatePicker;
import android.widget.TimePicker;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.DialogFragment;

import java.time.LocalDate;

public class TimePickerDialogFragment extends DialogFragment implements TimePickerDialog.OnTimeSetListener{

    @Override
    public void onTimeSet(TimePicker timePicker, int hour, int minute) {

        if (listener != null) {
            listener.onClickButton(hour,minute);
        }
    }

    public interface TimePickerDialogFragmentListener{
        void onClickButton(int hour,int minute);
    }

    private TimePickerDialogFragmentListener listener;

    public void onAttach(@NonNull Context context) {

        super.onAttach(context);

        if(context instanceof TimePickerDialogFragmentListener){
            listener = (TimePickerDialogFragmentListener) context;
        }
    }
    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState){
        int hour = 0;
        int minute = 0;


        Dialog timePickerDialog = new TimePickerDialog(getActivity(),this,hour,minute,true);
        return timePickerDialog;
    }
}

 

下記のようにスピナーモードを設定できます。

Dialog timePickerDialog = new TimePickerDialog(getActivity(),this,hour,minute,true);

⇒Dialog timePickerDialog = new TimePickerDialog(getActivity(),AlertDialog.THEME_HOLO_LIGHT,this,hour,minute,true);

ただし、何回か使っていると、００：０２：００で登録しても

１２：０２：００で登録されてしまうバグが発生してしまった。

⇒

ミリ秒を時間に変換する際の注意点 | Android-Note

 

 

以下でもよいようである。

Dialog timePickerDialog = new TimePickerDialog(getActivity(),this,hour,minute,true);

⇒Dialog timePickerDialog = new TimePickerDialog(getActivity(),android.R.style.Theme_Black,this,hour,minute,true);