Add getViewOrThrow() for convenience

thirtyinch/src/main/java/net/grandcentrix/thirtyinch/TiPresenter.java

@@ -300,7 +300,7 @@ public State getState() {
     }
 
     /**
-     * Returns the currently attached view. The view is attached between the lifecycle callbacks
+     * Gets the currently attached view. The view is attached between the lifecycle callbacks
      * {@link #onAttachView(TiView)} and {@link #onSleep()}.
      * <p>
      * If you don't care about the view being attached or detached you should either rethink your
@@ -314,6 +314,25 @@ public V getView() {
         return mView;
     }
 
+    /**
+     * Gets the currently attached view or throws an {@link IllegalStateException} if the view
+     * is not attached. Use this method if you are sure that a view is currently attached to the
+     * presenter. If you're not sure you should better use {@link #sendToView(ViewAction)} where the
+     * action will be executed when the view is attached.
+     *
+     * @return the currently attached view of this presenter
+     */
+    @NonNull
+    public V getViewOrThrow() {
+        final V view = getView();
+        if (view == null) {
+            throw new IllegalStateException(
+                    "The view is currently not attached. Use 'sendToView(ViewAction)' instead.");
+        }
+
+        return view;
+    }
+
     public boolean isDestroyed() {
         return mState == State.DESTROYED;
     }

thirtyinch/src/test/java/net/grandcentrix/thirtyinch/TiPresenterTest.java

@@ -29,8 +29,10 @@
 
 import static junit.framework.Assert.assertEquals;
 import static junit.framework.Assert.assertNotSame;
+import static junit.framework.Assert.assertNull;
 import static junit.framework.Assert.assertTrue;
 import static junit.framework.Assert.fail;
+import static org.assertj.core.api.Assertions.failBecauseExceptionWasNotThrown;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -273,7 +275,37 @@ protected void onDestroy() {
     }
 
     @Test
-    public void testGetView() throws Exception {
+    public void testGetViewOrThrow() {
+        mPresenter.create();
+        mPresenter.attachView(mView);
+        mPresenter.detachView();
+
+        try {
+            mPresenter.getViewOrThrow();
+            failBecauseExceptionWasNotThrown(IllegalStateException.class);
+        } catch (IllegalStateException e) {
+            assertThat(e.getMessage(),
+                    equalTo("The view is currently not attached. Use 'sendToView(ViewAction)' instead."));
+        }
+    }
+
+    @Test
+    public void testGetViewOrThrowReturnsView() {
+        mPresenter.create();
+        mPresenter.attachView(mView);
+        assertThat(mPresenter.getViewOrThrow(), equalTo(mView));
+    }
+
+    @Test
+    public void testGetViewReturnsNull() {
+        mPresenter.create();
+        mPresenter.attachView(mView);
+        mPresenter.detachView();
+        assertNull(mPresenter.getView());
+    }
+
+    @Test
+    public void testGetViewReturnsView() {
         mPresenter.create();
         mPresenter.attachView(mView);
         assertThat(mPresenter.getView(), equalTo(mView));