android-context

问题 How to use SharedPreferences in a class without oncreate ? I get null pointer when accessing it. public class Ftr extends Activity { SharedPreferences preferences; Context ab=this; public void ft() { preferences = PreferenceManager.getDefaultSharedPreferences(ab); String result = preferences.getString("F",""); } } I'm calling Function ft() from another activity Ftr is just a class not an activity. How can I use SharedPreferences in this condition? 回答1: You can take in Common method or Utils

问题 What is the context that is passed int the onReceive method of a BroadcastReciver : public void onReceive (Context context, Intent intent) According to the official documentation: The Context in which the receiver is running. 回答1: A little research gives below result... For static receiver public class MyReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Log.e("PANKAJ", "Context class " + context.getClass().getName()); Log.e("PANKAJ",

问题 I am facing a big problem in calling non static method from static method. This is my code Class SMS { public static void First_function() { SMS sms = new SMS(); sms.Second_function(); } public void Second_function() { Toast.makeText(getApplicationContext(),"Hello",1).show(); // This i anable to display and cause crash CallingCustomBaseAdapters(); //this was the adapter class and i anable to call this also } I am able to call Second_function but unable to get Toast and CallCustomBaseAdapter()

问题 This is Android Project. Using Normal Build was successfull, but using signed Key i got this error : Execution failed for task ':transformClassesAndResourcesWithProguardForFlavorRelease'. > java.io.IOException: java.lang.IllegalArgumentException: Can't find common super class of [android/content/Context] (with 2 known super classes) and [com/onesignal/ADMMessageHandler] (with 1 known super classes) Any Idea ? Thanks in advance... 回答1: I think Proguard causes this problem. Add this line to

问题 In my application I am sending a port SMS to the mobile. And when the message is recieved I need to perform some task in my activity and update the UI. Manifest Declaration of receiver <receiver android:name="com.vfi.BinarySMSReceiver" > <intent-filter android:priority="10" > <action android:name="android.intent.action.DATA_SMS_RECEIVED" /> <data android:host="*" android:port="9512" android:scheme="sms" /> </intent-filter> </receiver> Receiver class public class BinarySMSReceiver extends

问题 I'm new to Android testing and I'm trying to create an ApplicationTestCase using a MockContext (well actually I'm trying to use a Renaming Mock Context). But I keep getting an AssertionFailedError. Here's my very basic code so far: AppTests.java package com.myProject.test; import android.test.ApplicationTestCase; public class AppTests extends ApplicationTestCase<MyApplication> { public AppTests() { super(MyApplication.class); } @Override protected void setUp() throws Exception { final

问题 I'm new to Android testing and I'm trying to create an ApplicationTestCase using a MockContext (well actually I'm trying to use a Renaming Mock Context). But I keep getting an AssertionFailedError. Here's my very basic code so far: AppTests.java package com.myProject.test; import android.test.ApplicationTestCase; public class AppTests extends ApplicationTestCase<MyApplication> { public AppTests() { super(MyApplication.class); } @Override protected void setUp() throws Exception { final

问题 I have a custom View class that extends Spinner. I'm trying to figure out what the correct way to talk to the Activity that it's embedded in is, when the user makes a selection. I see that the OnItemSelected listener gets a reference to the Adapter, but I'm not clear on whether or not I should be using this adapter and walking up its parent chain somehow, or if I should just talk directly to the context (for some reason that doesn't feel safe, even though I can't think of a way in which it

问题 I am using several SharedPreferences to store data in my app. Some preferences are used in a lot of activites. I know that the SharedPreferences are internally backed by a map for fast read-access and written to sdcard when settings are changed. I wonder which way is better if a sharedpreference is accessed by a lot of activies: Instantiate it in every activity using the activity context. Instantiate it in every activity, but using the application context. Put it in e.g. the Application class

问题 I've read that it is a mistake and a source of memory leaks in Android application to keep a long-lived references to a Context. But I don't understand if it is ok to create a class that looks like this one: public class HelperClass { private Context context; public HelperClass(Context context) { this.context = context; } public void myHelperMethod() { // uses this.context } } And call it from an Activity: public class MyActivity extends Activity { public void onCreate(Bundle