Renamed the existing attachListener() method to attach() and added convenient attachAll(), detach() and detachAll() methods.

Author: Rolf-Smit

demo/src/main/java/org/neotech/app/retainabletasksdemo/Main.java

@@ -48,10 +48,10 @@ protected void onCreate(Bundle savedInstanceState) {
     protected void onStart() {
         super.onStart();
         progressDialog = ProgressDialog.getExistingInstance(getSupportFragmentManager(), DIALOG_PROGRESS);
-        getTaskManager().attachListener(TASK_PROGRESS, this);
+        getTaskManager().attach(TASK_PROGRESS, this);
 
 
-        getTaskManager().attachListener(TASK_RETAIN_UI_STATE, new TaskManager.TaskAttachListener() {
+        getTaskManager().attach(TASK_RETAIN_UI_STATE, new TaskManager.TaskAttachListener() {
             @Override
             public Task.Callback onPreAttach(Task<?, ?> task) {
                 /**

library/src/main/java/org/neotech/library/retainabletasks/BaseTaskManager.java

@@ -2,6 +2,7 @@
 
 import android.support.annotation.MainThread;
 import android.support.annotation.NonNull;
+import android.support.v4.app.Fragment;
 import android.util.Log;
 
 import java.util.HashMap;
@@ -23,33 +24,67 @@ public class BaseTaskManager extends TaskManager {
 
     @Override
     @MainThread
-    public Task<?, ?> attachListener(@NonNull String tag, @NonNull Task.Callback callback){
+    public Task<?, ?> attach(@NonNull String tag, @NonNull Task.Callback callback){
         final Task<?, ?> task = tasks.get(tag);
         if(task == null){
             return null;
         }
-        task.setCallback(new CallbackShadow(callback));
-        return task;
+        return attach(task, callback);
     }
 
     @Override
     @MainThread
-    public Task<?, ?> attachListener(@NonNull String tag, @NonNull TaskAttachListener listener){
+    public Task<?, ?> attach(@NonNull String tag, @NonNull TaskAttachListener listener){
         final Task<?, ?> task = tasks.get(tag);
         if(task == null){
             return null;
         }
-        task.setCallback(new CallbackShadow(listener.onPreAttach(task)));
-        return task;
+        return attach(task, listener.onPreAttach(task));
     }
 
     @Override
-    @MainThread
-    public Task<?, ?> attachListener(@NonNull Task<?, ?> task, @NonNull Task.Callback callback) {
+    public Task<?, ?> attach(@NonNull Task<?, ?> task, @NonNull Task.Callback callback) {
+        logCallback(callback);
         task.setCallback(new CallbackShadow(callback));
         return task;
     }
 
+    @Override
+    public void attachAll(@NonNull Task.Callback callback, @NonNull String... tags) {
+        for(String tag: tags){
+            attach(tag, callback);
+        }
+    }
+
+    @Override
+    public void attachAll(@NonNull TaskAttachListener attachListener, @NonNull String... tags) {
+        for(String tag: tags){
+            attach(tag, attachListener);
+        }
+    }
+
+    @Override
+    public Task<?, ?> detach(@NonNull String tag) {
+        final Task<?, ?> task = tasks.get(tag);
+        if(task != null){
+            task.removeCallback();
+        }
+        return task;
+    }
+
+    @Override
+    public void detachAll(@NonNull String... tags) {
+        for(String tag: tags){
+            detach(tag);
+        }
+    }
+
+    private void logCallback(final Task.Callback callback){
+        if(callback instanceof Fragment || callback instanceof android.app.Fragment){
+            Log.i(TAG, "Important: Found attached Callback which is an instance of Fragment. If your Fragment doesn't follow the activity lifecycle make sure to detach the task in Fragment.onStop()!");
+        }
+    }
+
     @Override
     @MainThread
     public <Progress, Result> void execute(@NonNull Task<Progress, Result> task, @NonNull Task.Callback callback){

library/src/main/java/org/neotech/library/retainabletasks/TaskManager.java

@@ -2,6 +2,7 @@
 
 import android.support.annotation.MainThread;
 import android.support.annotation.NonNull;
+import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
 
 /**
@@ -37,14 +38,27 @@ public interface TaskAttachListener {
     @MainThread
     public abstract Task<?, ?> getTask(@NonNull String tag);
 
+
+    @MainThread
+    public abstract Task<?, ?> attach(@NonNull String tag, @NonNull Task.Callback callback);
+
+    @MainThread
+    public abstract Task<?, ?> attach(@NonNull String tag, @NonNull TaskAttachListener attachListener);
+
+    @MainThread
+    public abstract Task<?, ?> attach(@NonNull Task<?, ?> task, @NonNull Task.Callback callback);
+
+    @MainThread
+    public abstract void attachAll(@NonNull Task.Callback callback, @NonNull String... tags);
+
     @MainThread
-    public abstract Task<?, ?> attachListener(@NonNull String tag, @NonNull Task.Callback callback);
+    public abstract void attachAll(@NonNull TaskAttachListener attachListener, @NonNull String... tags);
 
     @MainThread
-    public abstract Task<?, ?> attachListener(@NonNull String tag, @NonNull TaskAttachListener attachListener);
+    public abstract Task<?, ?> detach(@NonNull String tag);
 
     @MainThread
-    public abstract Task<?, ?> attachListener(@NonNull Task<?, ?> task, @NonNull Task.Callback callback);
+    public abstract void detachAll(@NonNull String... tags);
 
     @MainThread
     public abstract Task<?, ?> cancel(@NonNull String tag);