Refactored LottieCompositionFactory APIs (#830)

Replaced existing `LottieComposition.Factory` methods with a new `LottieCompositionFactory`
The main purpose of this is to provide a clean way to handle exceptions. Today, parsing exceptions are thrown on a background thread and impossible to handle. This replaces that with a new `LottieResult` which mimics a typical `Result` class in functional programming. It either has a result or an exception.

The composition methods now return a `LottieTask<LottieResult<LottieComposition>>>`.
You can add/remove listeners on the LottieTask. The listener will be called with the result that contains either the exception or error.

This also deprecates all `LottieComposition.Factory` methods because they all have an analogous `LottieCompositionFactory` API.

This PR also extracts LottieAnimationView's cache into a separate class and added tests which found an off by one error.

#710

CHANGELOG.md

@@ -1,5 +1,8 @@
 # 2.6.0
 ### Features and Improvements
+* Deprecated `LottieComposition.Factory` in favor of LottieCompositionFactory.
+    * The new factory methods make it easier to catch exceptions by separating out success and
+    failure handlers. Previously, catching exceptions was impossible and would crash your app.
 * [Sample App] Added the ability to load a file from assets.
 
 # 2.5.7
@@ -12,15 +15,13 @@
 * Fixed a potential dangling Choreographer callback ([#775](https://githubcom/airbnb/lottie-android/pull/775))
 
 # 2.5.5
-# Bugs Fixed
 * Fixed end times for layers/animations. Before, if the layer/animation out frame was 20, it would fully render frame 20. This is incorrect. The last rendered frame should be 19.999... in this case. This should make Lottie reflect After Effects more accurately. However, if you are getting the frame in onAnimationEnd or onAnimationRepeat, it will be one less than it used to be.
 * Added support for base64 encoded images directly in the json instead of the filename. They are 33% larger than their equivalent image file but enables you to have images with a single file.
 * Fixed a lint error about KeyPath visibility.
 * A few min/max progress bug fixes.
 * Prevent autoPlay from starting before the animation was attached to the window. This caused animations in a RecyclerView to start playing before they were on screen.
 
 # 2.5.4
-# Bugs Fixed
 * You can now call playAnimation() from onAnimationEnd
 * Min/Max frames are clipped to the composition start/end
 * setProgress takes into account start and end frame

LottieSample/src/main/kotlin/com/airbnb/lottie/samples/LottieFontViewGroup.kt

@@ -12,6 +12,7 @@ import android.view.inputmethod.InputConnection
 import android.widget.FrameLayout
 import com.airbnb.lottie.LottieAnimationView
 import com.airbnb.lottie.LottieComposition
+import com.airbnb.lottie.LottieCompositionFactory
 import com.airbnb.lottie.LottieDrawable
 import java.util.*
 
@@ -25,20 +26,17 @@ class LottieFontViewGroup @JvmOverloads constructor(
 
     init {
         isFocusableInTouchMode = true
-        LottieComposition.Factory.fromAssetFileName(context, "Mobilo/BlinkingCursor.json"
-        ) { composition ->
-            if (composition == null) {
-                return@fromAssetFileName
-            }
-            cursorView.layoutParams = FrameLayout.LayoutParams(
-                    ViewGroup.LayoutParams.WRAP_CONTENT,
-                    ViewGroup.LayoutParams.WRAP_CONTENT
-            )
-            cursorView.setComposition(composition)
-            cursorView.repeatCount = LottieDrawable.INFINITE
-            cursorView.playAnimation()
-            addView(cursorView)
-        }
+        LottieCompositionFactory.fromAsset(context, "Mobilo/BlinkingCursor.json")
+                .addListener {
+                    cursorView.layoutParams = FrameLayout.LayoutParams(
+                            ViewGroup.LayoutParams.WRAP_CONTENT,
+                            ViewGroup.LayoutParams.WRAP_CONTENT
+                    )
+                    cursorView.setComposition(it)
+                    cursorView.repeatCount = LottieDrawable.INFINITE
+                    cursorView.playAnimation()
+                    addView(cursorView)
+                }
     }
 
     private fun addSpace() {
@@ -154,14 +152,11 @@ class LottieFontViewGroup @JvmOverloads constructor(
         if (compositionMap.containsKey(fileName)) {
             addComposition(compositionMap[fileName]!!)
         } else {
-            LottieComposition.Factory.fromAssetFileName(context, fileName
-            ) { composition ->
-                if (composition == null) {
-                    return@fromAssetFileName
-                }
-                compositionMap.put(fileName, composition)
-                addComposition(composition)
-            }
+            LottieCompositionFactory.fromAsset(context, fileName)
+                    .addListener {
+                        compositionMap.put(fileName, it)
+                        addComposition(it)
+                    }
         }
 
         return true

LottieSample/src/main/kotlin/com/airbnb/lottie/samples/LottiefilesViewModel.kt

@@ -6,6 +6,7 @@ import android.arch.lifecycle.Lifecycle
 import android.arch.lifecycle.MutableLiveData
 import android.arch.lifecycle.OnLifecycleEvent
 import android.util.Log
+import com.airbnb.lottie.L
 import com.airbnb.lottie.samples.model.AnimationData
 import com.airbnb.lottie.samples.model.AnimationResponse
 import io.reactivex.Observable
@@ -59,7 +60,7 @@ class LottiefilesViewModel(application: Application) : AndroidViewModel(applicat
                     responses.add(it)
                     animationDataList.value = flatten(animationDataList.value, it.data)
                 }, {
-                    Log.d("Gabe", "e#\t", it);
+                    Log.d(L.TAG, "e#\t", it);
                 }, {
                     loading.value = false
                 }))

LottieSample/src/main/kotlin/com/airbnb/lottie/samples/PlayerFragment.kt

@@ -15,6 +15,7 @@ import android.support.transition.TransitionManager
 import android.support.v4.app.Fragment
 import android.support.v4.content.ContextCompat
 import android.support.v7.app.AppCompatActivity
+import android.util.Log
 import android.view.*
 import android.widget.EditText
 import androidx.view.children
@@ -146,7 +147,8 @@ class PlayerFragment : Fragment() {
             onCompositionLoaded(it)
         })
         viewModel.error.observe(this, Observer {
-            Snackbar.make(coordinatorLayout, R.string.composition_load_error, Snackbar.LENGTH_LONG)
+            Snackbar.make(coordinatorLayout, R.string.composition_load_error, Snackbar.LENGTH_LONG).show()
+            Log.w(L.TAG, "Error loading composition.", viewModel.error.value);
         })
         viewModel.fetchAnimation(args)
 

LottieSample/src/main/kotlin/com/airbnb/lottie/samples/PlayerViewModel.kt

@@ -10,6 +10,7 @@ import android.net.Uri
 import android.os.Handler
 import android.os.Looper
 import com.airbnb.lottie.LottieComposition
+import com.airbnb.lottie.LottieCompositionFactory
 import com.airbnb.lottie.samples.model.CompositionArgs
 import io.reactivex.Observable
 import io.reactivex.android.schedulers.AndroidSchedulers
@@ -87,17 +88,13 @@ class PlayerViewModel(application: Application) : AndroidViewModel(application)
     }
 
     private fun handleJsonResponse(jsonString: String) {
-        try {
-            LottieComposition.Factory.fromJsonString(jsonString, {
-                if (it == null) {
-                    error.value = IllegalArgumentException("Unable to parse composition")
-                } else {
-                    composition.value = CompositionData(it)
+        LottieCompositionFactory.fromJsonString(jsonString)
+                .addListener {
+                    this.composition.value = CompositionData(it)
+                }
+                .addFailureListener {
+                    this.error.value = it
                 }
-            })
-        } catch (e: RuntimeException) {
-            error.value = e
-        }
     }
 
     @SuppressLint("CheckResult")
@@ -114,7 +111,8 @@ class PlayerViewModel(application: Application) : AndroidViewModel(application)
                             if (zipEntry.name.contains("__MACOSX")) {
                                 zis.closeEntry()
                             } else if (zipEntry.name.contains(".json")) {
-                                val composition = LottieComposition.Factory.fromInputStreamSync(zis, false)
+                                val result = LottieCompositionFactory.fromJsonInputStreamSync(zis, false)
+                                val composition = result.value
                                 if (composition == null) {
                                     throw IllegalArgumentException("Unable to parse composition")
                                 } else {
@@ -160,22 +158,22 @@ class PlayerViewModel(application: Application) : AndroidViewModel(application)
             return
         }
 
-        LottieComposition.Factory.fromInputStream(fis) {
-            if (it == null) {
-                error.value = IllegalArgumentException("Er")
-            } else {
-                composition.value = CompositionData(it)
-            }
-        }
+        LottieCompositionFactory.fromJsonInputStream(fis)
+                .addListener {
+                    this.composition.value = CompositionData(it)
+                }
+                .addFailureListener {
+                    this.error.value = it
+                }
     }
 
     private fun fetchAnimationByAsset(asset: String) {
-        LottieComposition.Factory.fromAssetFileName(getApplication(), asset) {
-            if (it == null) {
-                error.value = IllegalArgumentException("Error loading asset " + asset)
-            } else {
-                composition.value = CompositionData(it)
-            }
-        }
+        LottieCompositionFactory.fromAsset(getApplication(), asset)
+                .addListener {
+                    composition.value = CompositionData(it)
+                }
+                .addFailureListener {
+                    error.value = it
+                }
     }
 }