android实现具有闹铃功能的闹钟的代码和布局文件

以下是一个简单的实现具有闹铃功能的闹钟的 Android 代码和布局文件：

布局文件 alarm_clock.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    
    <TextView
        android:id="@+id/textViewTime"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="80sp"
        android:gravity="center" />
    
    <Button
        android:id="@+id/buttonSetAlarm"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Set Alarm" />
    
    <Button
        android:id="@+id/buttonCancelAlarm"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Cancel Alarm"
        android:visibility="gone" />
    
</LinearLayout>

Java 代码 AlarmClockActivity.java：

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Locale;

public class AlarmClockActivity extends AppCompatActivity {

    private TextView textViewTime;
    private Button buttonSetAlarm;
    private Button buttonCancelAlarm;

    private AlarmManager alarmManager;
    private PendingIntent alarmIntent;

    private boolean isAlarmSet = false;

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

        textViewTime = findViewById(R.id.textViewTime);
        buttonSetAlarm = findViewById(R.id.buttonSetAlarm);
        buttonCancelAlarm = findViewById(R.id.buttonCancelAlarm);

        alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        Intent intent = new Intent(this, AlarmReceiver.class);
        alarmIntent = PendingIntent.getBroadcast(this, 0, intent, 0);

        buttonSetAlarm.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                setAlarm();
            }
        });

        buttonCancelAlarm.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                cancelAlarm();
            }
        });
    }

    private void setAlarm() {
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.add(Calendar.SECOND, 10);

        alarmManager.setExact(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), alarmIntent);

        SimpleDateFormat sdf = new SimpleDateFormat("hh:mm:ss a", Locale.getDefault());
        textViewTime.setText(sdf.format(calendar.getTime()));

        isAlarmSet = true;
        buttonSetAlarm.setVisibility(View.GONE);
        buttonCancelAlarm.setVisibility(View.VISIBLE);
    }

    private void cancelAlarm() {
        alarmManager.cancel(alarmIntent);

        textViewTime.setText("");
        isAlarmSet = false;
        buttonSetAlarm.setVisibility(View.VISIBLE);
        buttonCancelAlarm.setVisibility(View.GONE);
    }

    @Override
    protected void onResume() {
        super.onResume();

        if (isAlarmSet) {
            buttonSetAlarm.setVisibility(View.GONE);
            buttonCancelAlarm.setVisibility(View.VISIBLE);
        } else {
            buttonSetAlarm.setVisibility(View.VISIBLE);
            buttonCancelAlarm.setVisibility(View.GONE);
        }
    }
}

Java 代码 AlarmReceiver.java：

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.media.MediaPlayer;
import android.widget.Toast;

public class AlarmReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context, "Alarm triggered!", Toast.LENGTH_LONG).show();

        MediaPlayer mediaPlayer = MediaPlayer.create(context, R.raw.alarm_sound);
        mediaPlayer.start();
    }
}

在 res/raw 文件夹下添加一个音频文件 alarm_sound.mp3。

这个代码可以让用户在界面上设置闹钟时间，并且在闹钟时间到达时播放音频文件。用户可以取消闹钟。