java如何获取当前顶级活动上下文
在我的静态方法(参数只有一个字符串)中,我想使用Dialog(new AlertDialog.Builder(mContext)
),但Dialog需要一个活动上下文来构造。如果我不通过外部上下文参数,仅通过反射或其他方法,如何获取当前顶级活动的对象
public static Activity getActivity() {
Class activityThreadClass = null;
try {
activityThreadClass = Class.forName("安卓.app.ActivityThread");
Object activityThread = activityThreadClass.getMethod("currentActivityThread").invoke(null);
Field activitiesField = activityThreadClass.getDeclaredField("mActivities");
activitiesField.setAccessible(true);
Map activities = (Map) activitiesField.get(activityThread);
for (Object activityRecord : activities.values()) {
Class activityRecordClass = activityRecord.getClass();
Field pausedField = activityRecordClass.getDeclaredField("paused");
pausedField.setAccessible(true);
if (!pausedField.getBoolean(activityRecord)) {
Field activityField = activityRecordClass.getDeclaredField("activity");
activityField.setAccessible(true);
Activity activity = (Activity) activityField.get(activityRecord);
return activity;
}
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
return null;
}
我使用了这段代码,但当我在非活动类中调用此方法时,activities
为空
还有别的办法吗?不能使用对话框,只要能弹出信息就可以被用户看到。点限制:不从参数获取上下文
# 1 楼答案
使用^{}
实施示例:
在自定义应用程序类中: