能帮我看下这句代码为什么报错吗PermissionUtil = (AlarmManager) getSystemService(Context.ALARM_SERVICE); boolean hasAlarmPermission = PermissionUtil.judgeHasPermissions(this, Mani
时间: 2023-08-23 21:09:19 浏览: 59
这段代码报错的原因是因为 `PermissionUtil` 这个对象并没有被定义或者初始化。在这段代码中,你试图使用 `AlarmManager` 和 `Context` 对象来获取权限,但是你并没有定义一个 `PermissionUtil` 对象来调用 `judgeHasPermissions` 方法。你需要先创建一个 `PermissionUtil` 类或者对象,然后再调用 `judgeHasPermissions` 方法。例如:
```java
PermissionUtil permissionUtil = new PermissionUtil();
boolean hasAlarmPermission = permissionUtil.judgeHasPermissions(this, Manifest.permission.SET_ALARM);
```
同时,你需要确保在 AndroidManifest.xml 文件中添加了 SET_ALARM 权限声明,否则也会导致该代码报错。
相关问题
帮我写完整的代码实现闹铃功能。在Timepicker选择好闹铃时间后,在闹铃的时间时响起MP3音乐。
好的,以下是实现闹铃功能的代码:
```
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TimePicker;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import java.util.Calendar;
public class MainActivity extends AppCompatActivity {
private TimePicker timePicker;
private Button setAlarmButton;
private MediaPlayer mediaPlayer;
private boolean isPlaying = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
timePicker = findViewById(R.id.timePicker);
setAlarmButton = findViewById(R.id.setAlarmButton);
setAlarmButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int hour = timePicker.getCurrentHour();
int minute = timePicker.getCurrentMinute();
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, hour);
calendar.set(Calendar.MINUTE, minute);
calendar.set(Calendar.SECOND, );
setAlarm(calendar.getTimeInMillis());
}
});
}
private void setAlarm(long timeInMillis) {
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(this, AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, , intent, );
alarmManager.setExact(AlarmManager.RTC_WAKEUP, timeInMillis, pendingIntent);
Toast.makeText(this, "闹铃设置成功", Toast.LENGTH_SHORT).show();
}
public void startAlarm() {
if (!isPlaying) {
mediaPlayer = MediaPlayer.create(this, R.raw.alarm_sound);
mediaPlayer.start();
isPlaying = true;
}
}
public void stopAlarm() {
if (isPlaying) {
mediaPlayer.stop();
mediaPlayer.release();
isPlaying = false;
}
}
}
```
在这个代码中,我们使用了 Android 的 AlarmManager 来设置闹铃,当闹铃时间到达时,会触发一个广播,我们在广播接收器中播放 MP3 音乐。以下是广播接收器的代码:
```
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
MainActivity activity = (MainActivity) context;
activity.startAlarm();
}
}
```
在这个广播接收器中,我们通过 context 获取到 MainActivity 的实例,然后调用 MainActivity 中的 startAlarm() 方法来播放音乐。当用户点击停止闹铃按钮时,我们会调用 MainActivity 中的 stopAlarm() 方法来停止播放音乐。
请帮我写完整的可以运行的代码。利用一个Timepicker控件和一个imagebutton实现闹钟功能。通过点击按钮,开启闹钟,再次点击按钮,关闭闹钟。闹钟触发时循环播放MP3音乐,点击按钮可取消播放。
好的,以下是可以运行的代码:
XML布局文件:
<?xml version="1." encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TimePicker
android:id="@+id/timePicker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
<ImageButton
android:id="@+id/alarmButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/timePicker"
android:layout_centerHorizontal="true"
android:src="@drawable/ic_alarm_off" />
</RelativeLayout>
Java代码:
public class MainActivity extends AppCompatActivity {
private TimePicker timePicker;
private ImageButton alarmButton;
private MediaPlayer mediaPlayer;
private boolean isPlaying = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
timePicker = findViewById(R.id.timePicker);
alarmButton = findViewById(R.id.alarmButton);
alarmButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (!isPlaying) {
// 开启闹钟
setAlarm();
} else {
// 关闭闹钟
cancelAlarm();
}
}
});
}
private void setAlarm() {
// 获取闹钟时间
int hour = timePicker.getCurrentHour();
int minute = timePicker.getCurrentMinute();
// 创建闹钟
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(this, AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, , intent, );
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, hour);
calendar.set(Calendar.MINUTE, minute);
calendar.set(Calendar.SECOND, );
long triggerTime = calendar.getTimeInMillis();
alarmManager.setExact(AlarmManager.RTC_WAKEUP, triggerTime, pendingIntent);
// 播放音乐
mediaPlayer = MediaPlayer.create(this, R.raw.alarm);
mediaPlayer.setLooping(true);
mediaPlayer.start();
isPlaying = true;
alarmButton.setImageResource(R.drawable.ic_alarm_on);
}
private void cancelAlarm() {
// 取消闹钟
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(this, AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, , intent, );
alarmManager.cancel(pendingIntent);
// 停止音乐
mediaPlayer.stop();
mediaPlayer.release();
isPlaying = false;
alarmButton.setImageResource(R.drawable.ic_alarm_off);
}
}
闹钟接收器代码:
public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// 播放音乐
MediaPlayer mediaPlayer = MediaPlayer.create(context, R.raw.alarm);
mediaPlayer.setLooping(true);
mediaPlayer.start();
}
}
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