![](/img/trans.png)
[英]Unable to find explicit activity class. in AndroidManifest.xml
[英]Android: Unable to find explicit activity class even though I defined it in AndroidManifest.xml?
我正在編寫一個簡單的應用程序,它在應用程序啟動 5 秒后觸發警報,其中啟動了另一個活動(AlarmDialog)。 但是,當我運行我的應用程序時,出現以下錯誤:
原因:android.content.ActivityNotFoundException:無法找到顯式活動 class {com.example.basicalarmsetter/AlarmDialog}; 您是否在 AndroidManifest.xml 中聲明了此活動?
這似乎很奇怪,考慮到我相信我已經在我的AndroidManifest.xml 文件中聲明了該活動:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.basicalarmsetter">
<uses-permission android:name="com.android.alarm.permission.SET_ALARM" />
<application
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="MainActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".AlarmDialog"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat.Light.NoActionBar">
</activity>
<receiver android:name=".AlarmReceiver"/>
</application>
</manifest>
以下是我的應用程序其他類的代碼:
MainActivity.java :
package com.example.basicalarmsetter;
import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
public class MainActivity extends Activity {
private Context context;
private AlarmManager alarmMgr;
private PendingIntent alarmIntent;
// Creates the Pending Intent used to set off the alarm
private PendingIntent generateAlarmPendingIntent(Context context) {
Intent intent = new Intent(context, AlarmReceiver.class);
// Each alarm requires a unique id
int alarmId = (int) (Math.random() * (10000 - 1 + 1) + 1);
System.out.println("alarmId = " + alarmId);
PendingIntent alarmPendingIntent = PendingIntent.getBroadcast(context, alarmId, intent, 0);
return alarmPendingIntent;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context = getApplicationContext();
// Set an alarm 5 seconds after now
alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
alarmMgr.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + 5000,
generateAlarmPendingIntent(context));
}
}
警報接收器:
package com.example.basicalarmsetter;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context k1, Intent k2) {
System.out.println("Alarm received!");
Intent i = new Intent();
i.setClassName("com.example.basicalarmsetter", "AlarmDialog");
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
k1.startActivity(i);
}
}
警報對話框:
package com.example.basicalarmsetter;
import android.app.Activity;
import android.os.Bundle;
public class AlarmDialog extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.alarm_dialog);
}
}
文件結構:所有類MainActivity
、 AlarmDialog
和AlarmReceiver
都在同一目錄下。
代替:
Intent i = new Intent();
i.setClassName("com.example.basicalarmsetter", "AlarmDialog");
和:
Intent i = new Intent(k1, AlarmDialog.class);
這將使用更好的構造函數,有助於避免硬編碼字符串中的錯誤。 作為獎勵,如果您使用 IDE 重命名AlertDialog
,您的Intent
也會被修改。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.