Loaders and cursors for DBFlow #1091

hilljh82 · 2016-12-01T01:13:05Z

This pull request contains the implementation of the following classes to improve Loader support for DBFlow.

FlowCursorAdapter: The purpose of this class is to improve support for CursorAdapter. In particular, we overload the getItem (position) method to return the actual model element at that position instead of a Cursor.
FlowSimpleCursorAdapter: This class allows the SimpleCursorAdapter to easily support DBFlow. Similar to FlowCursorAdapter, we overload the getItem(position) method to return a model element, instead of a Cursor.
FlowCursorLoader: This class integrates DBFLow with the Android Loader framework. In particular, the loader must be created with a Queriable object. The Queriable object is used by the loader to load models. The end result of this loader is a Cursor that can be used like the cursor returned by CursorLoader. A key feature of this loader is the ability to leverage the model observer framework in DBFlow via the (un)registerForContentChanges() methods. Using this methods will configure the loader to observe changes to models of interest. Any change observed will trigger the loader to automatically reload. This simplifies storing data in the database via DBFlow models, and updating corresponding views as a result of the storage updates.
FlowSingleModelLoader: This is the base class for the following single model classes: FlowModelLoader, FlowModelViewLoader, FlowModelQueryLoader. Single model loaders are for queries that return 1 model, not a list of models or a cursor to a list of models. We treat these different from the list loaders because we need to appropriate InstanceAdapter to create the single model, and load it from the cursor. The result of each load is a single, usable model. Similar to the FlowModelLoader, these loaders will automatically reload if the underlying table changes. Also, you can register for updates to models that have nothing to do with the final model. This is of interest when dealing with query models since the final model may be the composition of data from many different tables.

Lastly, each loader has been tested in applications that I am currently using. It would be great if these classes can be incorporated into the next release of DBFlow.

…el container

agrosner · 2016-12-01T14:37:31Z

...nextensions/src/main/java/com/raizlabs/android/dbflow/kotlinextensions/PropertyExtensions.kt

@@ -35,6 +34,6 @@ val <T : Any> T.property: Property<T>
 val <T : Any> ModelQueriable<T>.property: Property<T>
    get() = PropertyFactory.from(this)

-inline fun <reified T : Any> T.propertyString(stringRepresentation: String?): Property<T> {
-    return PropertyFactory.from(T::class.java, stringRepresentation)
+inline fun <reified TModel : Any> TModel.propertyString(stringRepresentation: String?): Property<TModel> {


#? not sure why this type parameter changed?

agrosner · 2016-12-01T14:39:03Z

dbflow-processor/src/main/java/com/raizlabs/android/dbflow/processor/ClassNames.java

@@ -0,0 +1,117 @@
+package com.raizlabs.android.dbflow.processor;


#req remove this file. It was added back, in develop its a kotlin file.

@agrosner I am will take care of that now. I am looking at the changed files to resolve other issues that are similar to this one.

… have been modified

agrosner · 2016-12-01T14:41:01Z

dbflow/src/main/java/com/raizlabs/android/dbflow/list/FlowCursorAdapter.java

+ * @param <TModel>
+ */
+public abstract class FlowCursorAdapter <TModel extends Model> extends CursorAdapter {
+    private final ModelAdapter<TModel> mModelAdapter;


#req naming. no m-prefix names please.

agrosner · 2016-12-01T14:41:44Z

dbflow/src/main/java/com/raizlabs/android/dbflow/list/FlowCursorAdapter.java

+    @Override
+    public TModel getItem(int position) {
+        Cursor cursor = (Cursor) super.getItem(position);
+        return cursor != null ? this.mModelAdapter.loadFromCursor(cursor) : null;


we might want to use a FlowCursorList here so we can provide caching.

agrosner · 2016-12-01T14:42:15Z

dbflow/src/main/java/com/raizlabs/android/dbflow/list/FlowCursorLoader.java

+@TargetApi(11)
+public class FlowCursorLoader extends AsyncTaskLoader<Cursor> {
+    /// Models to be observed for changes.
+    private final HashSet<Class<? extends Model>> mModels = new HashSet<>();


#req no m-prefix variables please.

agrosner · 2016-12-01T14:42:40Z

dbflow/src/main/java/com/raizlabs/android/dbflow/list/FlowCursorLoader.java

+        Cursor cursor = this.mQueriable.query();
+
+        if (cursor != null) {
+            cursor.getCount();


#? what is this supposed to do

This forces the cursor to load the load the count.

agrosner · 2016-12-01T14:43:58Z

dbflow/src/main/java/com/raizlabs/android/dbflow/list/FlowCursorLoader.java

+        }
+    }
+
+    public Collection<Class<? extends Model>> getModels() {


#req rename to something like getModelClasses()

agrosner · 2016-12-01T14:44:59Z

dbflow/src/main/java/com/raizlabs/android/dbflow/list/FlowCursorLoader.java

+        @Override
+        public void onModelStateChanged(@Nullable Class<?> table, BaseModel.Action action, @NonNull SQLCondition[] primaryKeyValues) {
+            if (!this.endOfTransaction) {
+                if (action == BaseModel.Action.INSERT || action == BaseModel.Action.DELETE || action == BaseModel.Action.UPDATE) {


#? what about the other two, CHANGE + SAVE?

Is CHANGE new? I did not add SAVE since for some reasons I was seeing SAVE being fired with either INSERT or UPDATE in 3.1.x. So, it was triggering the loader twice. Is this a true understanding of those events being fired.

How is CHANGE different from UPDATE?

agrosner · 2016-12-01T14:46:01Z

dbflow/src/main/java/com/raizlabs/android/dbflow/list/FlowSimpleCursorAdapter.java

+ *
+ * @param <TModel>
+ */
+public class FlowSimpleCursorAdapter <TModel extends Model> extends SimpleCursorAdapter {


#? not sure the difference here between this and the FlowCursorAdapter

This Adapter is specialization of the SimpleCursorAdapter in the Android SDK designed for DBFlow.

The FlowCursorAdapter requires allows the developer to have different layouts for model. For example, you are storing inherited data in a SQL database, and create a query that aggregates different model types into a single result set. In this case, you have a different layout for each data type referenced in the data set. You therefore have to implement newView and bindView.

In some cases, however, the data you result set will be a homogenous data types, and the mapping between columns and views is straightforward text populations. In this case, you only need a single layout, and a mapping between columns and views. The FlowSimpleCursorAdapter is designed to support this need since you only have to provide the layout id and the necessary mapping in the constructor.

agrosner · 2016-12-01T14:47:09Z

dbflow/src/main/java/com/raizlabs/android/dbflow/single/FlowModelViewLoader.java

+ * @param <TModel>
+ */
+@TargetApi(11)
+public class FlowModelViewLoader <TModel extends Model, TModelView extends BaseModelView>


#req no Model restriction on the TModel

#? How do you ensure the class is only parameterized by DBFlow Model-like classes? Is this no longer a concern with 4.x.x? Also, doing so will mean removing restrictions on certain methods that should only be called with class that derive from Model, such as registerForContentChanges. This would be an introduction of an accidental complicity in the design.

agrosner · 2016-12-01T14:47:33Z

dbflow/src/main/java/com/raizlabs/android/dbflow/single/FlowModelLoader.java

+ * @param <TModel>
+ */
+@TargetApi(11)
+public class FlowModelLoader <TModel extends Model>


#req no model restriction anywhere please.

#? How do you ensure the class is only parameterized by DBFlow Model-like classes? Is this no longer a concern with 4.x.x? Also, doing so will mean removing restrictions on certain methods that should only be called with class that derive from Model, such as registerForContentChanges. This would be an introduction of an accidental complicity in the design.

agrosner · 2016-12-01T14:48:15Z

usage2/SQLiteWrapperLanguage.md

@@ -269,7 +269,7 @@ Delete.tables(MyTable1.class, MyTable2.class);

 // Delete using query
 SQLite.delete(MyTable.class)
-  .where(DeviceObject_Table.carrier.is("T-MOBILE"))
+  .where(DeviceObject_Table.carrier.is("TModel-MOBILE"))


#req looks like you did some kind of refactor that change T to TModel. haha oops.

In the great words of Homer Simpson, "DOH!!!"

hilljh82 · 2016-12-06T23:52:51Z

@agrosner Is there anything blocking this PR for being merged?

hannesa2 · 2016-12-18T07:54:39Z

This PR is a key feature for me.
@hilljh82 is not alone, I'm happy when this PR is merged soon

hannesa2 · 2017-03-02T13:18:20Z

@hilljh82 please solve the conflict to let us (who wait for this feature) know, if @agrosner ever will merge this PR. Thank you !

zubinmehta · 2017-03-21T10:40:57Z

@hilljh82 I am trying to use FlowCursorLoader class. It works but sometimes, I get

java.lang.IllegalStateException: Cannot execute task: the task is already running.
at android.support.v4.content.ModernAsyncTask.executeOnExecutor(ModernAsyncTask.java:424)
at android.support.v4.content.AsyncTaskLoader.executePendingTask(AsyncTaskLoader.java:219)
at android.support.v4.content.AsyncTaskLoader.dispatchOnCancelled(AsyncTaskLoader.java:232)
at android.support.v4.content.AsyncTaskLoader$LoadTask.onCancelled(AsyncTaskLoader.java:88)
at android.support.v4.content.ModernAsyncTask.finish(ModernAsyncTask.java:474)
at android.support.v4.content.ModernAsyncTask$InternalHandler.handleMessage(ModernAsyncTask.java:493)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5438)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629)

Googled a lot but no success. I am probably doing something wrong.
I wonder, if you ever got this issue and/or know how to fix this?

Thanks !

hilljh82 · 2017-03-21T12:12:55Z

No, I have not. Do you mind sharing the code where you are creating the loader? On Tue, Mar 21, 2017, 6:41 AM Zubin Mehta <[email protected]> wrote: @hilljh82 <https://github.com/hilljh82> I am trying to use FlowCursorLoader class. It works but sometimes, I get java.lang.IllegalStateException: Cannot execute task: the task is already running. at android.support.v4.content.ModernAsyncTask.executeOnExecutor(ModernAsyncTask.java:424) at android.support.v4.content.AsyncTaskLoader.executePendingTask(AsyncTaskLoader.java:219) at android.support.v4.content.AsyncTaskLoader.dispatchOnCancelled(AsyncTaskLoader.java:232) at android.support.v4.content.AsyncTaskLoader$LoadTask.onCancelled(AsyncTaskLoader.java:88) at android.support.v4.content.ModernAsyncTask.finish(ModernAsyncTask.java:474) at android.support.v4.content.ModernAsyncTask$InternalHandler.handleMessage(ModernAsyncTask.java:493) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5438) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629) I have been stuck at this issue, after googling a lot. I am probably doing something wrong. I wonder, if you ever got this issue and/or know how to fix this? Thanks ! — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1091 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AB7C_QGHPrDHeGBWoU_rYDskdynf5yR9ks5rn6k9gaJpZM4LA5AA> .

Harti · 2017-10-26T15:51:34Z

sigh I really hate to see this PR just go to waste.

@agrosner Did you make a final decision on declining this PR yet?

hilljh82 · 2017-10-27T00:17:59Z

@Harti Yes, it is unfortunate this PR has not been integrated into master—especially since I have twice addressed merge conflicts due to master changing only for my updates to become outdated once again.

If you are interested, I have create a separate project that provides these loaders:

https://github.com/onehilltech/backbone/tree/master/backbone-dbflow

Until this PR gets merged, I have been using this project. It is also a place that I use to implement support classes for DBFlow since the experience with this PR leaves me with little confidence some cool ideas I have will ever be integrated!

In addition, I have been working on another project called backbone-data that is designed to the equivalent of ember-data for Android. It uses DBFlow and Retrofit under the hood. It's a work in progress, but its making my life a LOT easier on Android since it codifies much if the redundant code that I was creating when using DBFlow.

hilljh82 added 30 commits January 30, 2016 19:46

First pass at external foreign key references

91326fb

Added missing files

50382fc

Merge from Raizlabs

a1ff768

Foreign key on primary key failed if column was a model and not a mod…

35567d3

…el container

Removed debug code

a92a9d1

Overrided getSupportedOptions() to handle processor warnings

de30375

Foreign key definition failed with model container

bf4b415

Reverted change

50e409b

Removed test files

6dfd5d6

Merge from raizlabs/develop

f3935e1

Added missing code for checkNeedsReferences()

0947f8c

Removed faulty line of code

118204a

Added missing check for external foreign key

2a450a2

Overrided the newInstance() method

36b7fa7

Merge from Raizlabs/master

f98ebc2

Fixed error preventing Jitpack from working

9431b13

Merge from master

e483520

Fixed build errors

1e05a47

Fixed build error

ccdb83b

Fixed compilation errors

49d3993

Merge branch 'master' into develop

25403c8

Switch to AsyncTaskLoader in Android support library

e3b8ecb

Added missing dependency

536a5bb

Fixed build issues with API version

36b144d

Merge from Raizlabs/develop

cff3e40

Merge from Raizlabs/master

09f1be7

Merge branch 'master' into develop

956fc1b

Fixed issues in implementation

63fe220

Loaders for single model queries

008dc04

Relocated file

a7105b4

hilljh82 added 2 commits December 1, 2016 09:34

Fixed formatting issues

0554ec4

For some reason, lintOptions was added to the build config

8d72965

agrosner reviewed Dec 1, 2016

View reviewed changes

PropertyExtensions was changed during the merge; this file should not…

d019191

… have been modified

agrosner reviewed Dec 1, 2016

View reviewed changes

Removed obsolete file

aff9722

agrosner reviewed Dec 1, 2016

View reviewed changes

hilljh82 added 6 commits December 1, 2016 11:23

Fixed naming convention on class variables

a613727

Fixed naming convention on class variables

d7d188e

Fixed refactoring error

c97f1b3

Fixed refactoring error

83ac02d

Fixed naming conventions errors

4cd5e39

Fixed naming conventions errors

0067c1e

ka05 mentioned this pull request Mar 20, 2018

Can you add documentation? onehilltech/backbone#1

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Loaders and cursors for DBFlow #1091

Loaders and cursors for DBFlow #1091

hilljh82 commented Dec 1, 2016

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		@@ -0,0 +1,117 @@
		package com.raizlabs.android.dbflow.processor;

Loaders and cursors for DBFlow #1091

Are you sure you want to change the base?

Loaders and cursors for DBFlow #1091

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