如何在Android的
问题描述:
嗨调用main_activity的方法,从一个普通的类我在后台进程使用这个职位Background process timer on android为timeer如何在Android的
在主要活动中我的计时器代码
int repeatTime = 5;
AlarmManager processTimer = (AlarmManager)getSystemService(ALARM_SERVICE);
Intent intent = new Intent(this, processTimerReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
processTimer.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(),repeatTime*1000, pendingIntent);
和我的代码类processTimerReceiver是:
public class processTimerReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
MainActivity m = new MainActivity();
m.get_start_info();
}
}
我要调用方法get_start_info()的主要活动,但应用程序崩溃
充满我的主要活动是:
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
setContentView(R.layout.activity_main);
int repeatTime = 5;
AlarmManager processTimer = (AlarmManager)getSystemService(ALARM_SERVICE);
Intent intent = new Intent(this, processTimerReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
processTimer.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(),repeatTime*1000, pendingIntent);
get_start_info();
}
public void get_start_info() {
JsonArrayRequest movieReq = new JsonArrayRequest("www.example.com",
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
try {
JSONObject obj = response.getJSONObject(0);
// any
sendNotification();
//any
} catch (Exception e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
AppController.getInstance().addToRequestQueue(movieReq);
}
public void sendNotification() {
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
builder.setSmallIcon(android.R.drawable.ic_dialog_email);
Uri soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
Intent intent = new Intent(MainActivity.this, azegar_mail_list.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
//mp.start();
builder.setContentIntent(pendingIntent);
builder.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher));
builder.setContentTitle("آزگار");
builder.setContentText("نامه جدید برای شما ارسال شده است");
builder.setAutoCancel(true);
builder.setSound(soundUri);
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
// Will display the notification in the notification bar
notificationManager.notify(1, builder.build());
}
}
我的错误是:
所有的E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start receiver com.azegar.www.azegar.processTimerReceiver: java.lang.NullPointerException
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2539)
at android.app.ActivityThread.access$1500(ActivityThread.java:167)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1432)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:153)
at android.app.ActivityThread.main(ActivityThread.java:5341)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:929)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.content.ContextWrapper.getResources(ContextWrapper.java:89)
at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:78)
at android.support.v7.app.AppCompatActivity.getResources(AppCompatActivity.java:551)
at android.content.Context.getString(Context.java:327)
at com.azegar.www.azegar.MainActivity.get_start_info(MainActivity.java:438)
at com.azegar.www.azegar.processTimerReceiver.onReceive(processTimerReceiver.java:12)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2532)
at android.app.ActivityThread.access$1500(ActivityThread.java:167)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1432)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:153)
at android.app.ActivityThread.main(ActivityThread.java:5341)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:929)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)
at dalvik.system.NativeStart.main(Native Method)
答
首先,如果你调用get_start_info()
外theMainActivity的,然后移动get_start_info()
和sendNotification
出MainActivity的。
你得到一个NullPointerException
,因为你要使用MainActivity
的背景下构建内部sendNotification
通知,这方面是零,因为您实例MainActivity
新的关键字(你不应该实例使用new关键字新的活动) 。相反,将BroadcastReceiver
的上下文作为参数传递给sendNotification
并用它来构建通知。
部件,它使用Context
代码:
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
Intent intent = new Intent(MainActivity.this, azegar_mail_list.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
在这里,用this
的instad,你应该使用作为参数传递的Context
。
嗨merterpam你的代码是非常好的代码为我工作谢谢 – ebrahim
嗨ebrehim,谢谢你,欢迎来到* =)。如果您对答案满意并想要结束该问题,请将答案标记为已接受。 – merterpam