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Extract the WindowInsetsAnimation.Callback subclass into a separate c…
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…lass that will be lazily loaded

WindowInsetsAnimation.Callback was introduced in API level 30.  This
PR moves the text input plugin's WindowInsetsAnimation.Callback subclass
into a class that will only be loaded if the embedding has checked for a
sufficient API level.

See flutter/flutter#66908
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jason-simmons committed Oct 1, 2020
1 parent 83b9df9 commit 700c7ca
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Showing 5 changed files with 181 additions and 161 deletions.
1 change: 1 addition & 0 deletions ci/licenses_golden/licenses_flutter
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Expand Up @@ -794,6 +794,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/common/StandardM
FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/common/StandardMethodCodec.java
FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/common/StringCodec.java
FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/editing/FlutterTextUtils.java
FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/editing/ImeSyncDeferringInsetsCallback.java
FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/editing/InputConnectionAdaptor.java
FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/editing/TextInputPlugin.java
FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/localization/LocalizationPlugin.java
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1 change: 1 addition & 0 deletions shell/platform/android/BUILD.gn
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Expand Up @@ -213,6 +213,7 @@ android_java_sources = [
"io/flutter/plugin/common/StandardMethodCodec.java",
"io/flutter/plugin/common/StringCodec.java",
"io/flutter/plugin/editing/FlutterTextUtils.java",
"io/flutter/plugin/editing/ImeSyncDeferringInsetsCallback.java",
"io/flutter/plugin/editing/InputConnectionAdaptor.java",
"io/flutter/plugin/editing/TextInputPlugin.java",
"io/flutter/plugin/localization/LocalizationPlugin.java",
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@@ -0,0 +1,175 @@
// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package io.flutter.plugin.editing;

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.graphics.Insets;
import android.view.View;
import android.view.WindowInsets;
import android.view.WindowInsetsAnimation;
import androidx.annotation.Keep;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.annotation.VisibleForTesting;
import java.util.List;

// Loosely based off of
// https://github.com/android/user-interface-samples/blob/master/WindowInsetsAnimation/app/src/main/java/com/google/android/samples/insetsanimation/RootViewDeferringInsetsCallback.kt
//
// When the IME is shown or hidden, it immediately sends an onApplyWindowInsets call
// with the final state of the IME. This initial call disrupts the animation, which
// causes a flicker in the beginning.
//
// To fix this, this class extends WindowInsetsAnimation.Callback and implements
// OnApplyWindowInsetsListener. We capture and defer the initial call to
// onApplyWindowInsets while the animation completes. When the animation
// finishes, we can then release the call by invoking it in the onEnd callback
//
// The WindowInsetsAnimation.Callback extension forwards the new state of the
// IME inset from onProgress() to the framework. We also make use of the
// onStart callback to detect which calls to onApplyWindowInsets would
// interrupt the animation and defer it.
//
// By implementing OnApplyWindowInsetsListener, we are able to capture Android's
// attempts to call the FlutterView's onApplyWindowInsets. When a call to onStart
// occurs, we can mark any non-animation calls to onApplyWindowInsets() that
// occurs between prepare and start as deferred by using this class' wrapper
// implementation to cache the WindowInsets passed in and turn the current call into
// a no-op. When onEnd indicates the end of the animation, the deferred call is
// dispatched again, this time avoiding any flicker since the animation is now
// complete.
@VisibleForTesting
@TargetApi(30)
@RequiresApi(30)
@SuppressLint({"NewApi", "Override"})
@Keep
class ImeSyncDeferringInsetsCallback extends WindowInsetsAnimation.Callback
implements View.OnApplyWindowInsetsListener {
private int overlayInsetTypes;
private int deferredInsetTypes;

private View view;
private WindowInsets lastWindowInsets;
// True when an animation that matches deferredInsetTypes is active.
//
// While this is active, this class will capture the initial window inset
// sent into lastWindowInsets by flagging needsSave to true, and will hold
// onto the intitial inset until the animation is completed, when it will
// re-dispatch the inset change.
private boolean animating = false;
// When an animation begins, android sends a WindowInset with the final
// state of the animation. When needsSave is true, we know to capture this
// initial WindowInset.
private boolean needsSave = false;

ImeSyncDeferringInsetsCallback(
@NonNull View view, int overlayInsetTypes, int deferredInsetTypes) {
super(WindowInsetsAnimation.Callback.DISPATCH_MODE_CONTINUE_ON_SUBTREE);
this.overlayInsetTypes = overlayInsetTypes;
this.deferredInsetTypes = deferredInsetTypes;
this.view = view;
}

void install() {
view.setWindowInsetsAnimationCallback(this);
view.setOnApplyWindowInsetsListener(this);
}

void remove() {
view.setWindowInsetsAnimationCallback(null);
view.setOnApplyWindowInsetsListener(null);
}

@Override
public WindowInsets onApplyWindowInsets(View view, WindowInsets windowInsets) {
this.view = view;
if (needsSave) {
// Store the view and insets for us in onEnd() below. This captured inset
// is not part of the animation and instead, represents the final state
// of the inset after the animation is completed. Thus, we defer the processing
// of this WindowInset until the animation completes.
lastWindowInsets = windowInsets;
needsSave = false;
}
if (animating) {
// While animation is running, we consume the insets to prevent disrupting
// the animation, which skips this implementation and calls the view's
// onApplyWindowInsets directly to avoid being consumed here.
return WindowInsets.CONSUMED;
}

// If no animation is happening, pass the insets on to the view's own
// inset handling.
return view.onApplyWindowInsets(windowInsets);
}

@Override
public void onPrepare(WindowInsetsAnimation animation) {
if ((animation.getTypeMask() & deferredInsetTypes) != 0) {
animating = true;
needsSave = true;
}
}

@Override
public WindowInsets onProgress(
WindowInsets insets, List<WindowInsetsAnimation> runningAnimations) {
if (!animating || needsSave) {
return insets;
}
boolean matching = false;
for (WindowInsetsAnimation animation : runningAnimations) {
if ((animation.getTypeMask() & deferredInsetTypes) != 0) {
matching = true;
continue;
}
}
if (!matching) {
return insets;
}
WindowInsets.Builder builder = new WindowInsets.Builder(lastWindowInsets);
// Overlay the ime-only insets with the full insets.
//
// The IME insets passed in by onProgress assumes that the entire animation
// occurs above any present navigation and status bars. This causes the
// IME inset to be too large for the animation. To remedy this, we merge the
// IME inset with other insets present via a subtract + reLu, which causes the
// IME inset to be overlaid with any bars present.
Insets newImeInsets =
Insets.of(
0,
0,
0,
Math.max(
insets.getInsets(deferredInsetTypes).bottom
- insets.getInsets(overlayInsetTypes).bottom,
0));
builder.setInsets(deferredInsetTypes, newImeInsets);
// Directly call onApplyWindowInsets of the view as we do not want to pass through
// the onApplyWindowInsets defined in this class, which would consume the insets
// as if they were a non-animation inset change and cache it for re-dispatch in
// onEnd instead.
view.onApplyWindowInsets(builder.build());
return insets;
}

@Override
public void onEnd(WindowInsetsAnimation animation) {
if (animating && (animation.getTypeMask() & deferredInsetTypes) != 0) {
// If we deferred the IME insets and an IME animation has finished, we need to reset
// the flags
animating = false;

// And finally dispatch the deferred insets to the view now.
// Ideally we would just call view.requestApplyInsets() and let the normal dispatch
// cycle happen, but this happens too late resulting in a visual flicker.
// Instead we manually dispatch the most recent WindowInsets to the view.
if (lastWindowInsets != null && view != null) {
view.dispatchApplyWindowInsets(lastWindowInsets);
}
}
}
}
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