UI 个组件在 TransitionManager 动画中不可见
UI components not visible in TransitionManager animations
这是 Java Android 应用程序中的一个问题,在 MainActivity 中有一个非常简单的自定义可拖动抽屉。
这是它在 Android 10(API 级别 29)模拟器上运行时的行为,这是预期的行为。
但问题是,当它在Android L (API level 21) 模拟器上运行时,它的行为出乎意料如下:
在动画期间,UI 组件不可见。但是当应用程序进入后台并返回时,它们就会变得可见。
应用程序的实现细节:
为了检测滑动/拖动触摸手势,使用了GestureDetectorCompat
。
当检测到滑动手势时,将启动自定义抽屉打开动画。
动画是使用 ConstraintSet
、ConstraintLayout
和 TransitionManager
.
实现的
这是触摸手势检测和 TransitionManager 动画的实现。
MainActivity.java
public class MainActivity extends AppCompatActivity {
private boolean mIsDrawerOpened;
private ConstraintLayout mRootConstraintLayout;
private final ConstraintSet mDrawerClosedConstraintSet = new ConstraintSet();
private final ConstraintSet mDrawerOpenedConstraintSet = new ConstraintSet();
private GestureDetectorCompat mGestureDetector;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_drawer_closed);
// Drawer is initially closed
mIsDrawerOpened = false;
mRootConstraintLayout = findViewById(R.id.rootConstraintLayout);
mDrawerClosedConstraintSet.clone(this, R.layout.activity_main_drawer_closed);
mDrawerOpenedConstraintSet.clone(this, R.layout.activity_main_drawer_opened);
mGestureDetector = new GestureDetectorCompat(
getApplicationContext(),
new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
// Drag / Fling gesture detected
// TODO: Recongnize unwanted drag / fling gestures and ignore them.
TransitionManager.beginDelayedTransition(mRootConstraintLayout);
// Drawer is closed?
if(!mIsDrawerOpened) {
// Open the drawer
mDrawerOpenedConstraintSet.applyTo(mRootConstraintLayout);
mIsDrawerOpened = true;
}
return true;
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
// Single tap detected
// TODO: If user has tapped on the drawer, do not close it.
TransitionManager.beginDelayedTransition(mRootConstraintLayout);
// Drawer is opened?
if(mIsDrawerOpened) {
// Close the drawer
mDrawerClosedConstraintSet.applyTo(mRootConstraintLayout);
mIsDrawerOpened = false;
}
return true;
}
@Override
public boolean onDown(MotionEvent e) {
return true;
}
}
);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
mGestureDetector.onTouchEvent(event);
return super.onTouchEvent(event);
}
}
这是关闭抽屉的布局XML。
res/layout/activity_main_drawer_closed.xml
<ConstraintLayout
android:id="@+id/rootConstraintLayout">
<ConstraintLayout
android:id="@+id/drawerConstraintLayout"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
<!-- Constraint start (left) of drawer to end (right) of parent (drawer is outside the parent) -->
app:layout_constraintStart_toEndOf="parent"
... >
<Button
android:id="@+id/button1"
android:text="1"
... />
<Button
android:id="@+id/button2"
android:text="2"
... />
</ConstraintLayout>
<ImageView
android:id="@+id/notch"
android:src="@drawable/drawer_notch"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@id/drawerConstraintLayout"
... />
</ConstraintLayout>
这是打开抽屉的布局XML。
res/layout/activity_main_drawer_opened.xml
<ConstraintLayout
android:id="@+id/rootConstraintLayout">
<ConstraintLayout
android:id="@+id/drawerConstraintLayout"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
<!-- Constraint end (right) of drawer to end (right) of parent (drawer is inside the parent) -->
app:layout_constraintEnd_toEndOf="parent"
... >
<Button
android:id="@+id/button1"
android:text="1"
... />
<Button
android:id="@+id/button2"
android:text="2"
... />
</ConstraintLayout>
<ImageView
android:id="@+id/notch"
android:src="@drawable/drawer_notch"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@id/drawerConstraintLayout"
... />
</ConstraintLayout>
来自这 2 个布局的约束集被用作动画的开始和结束关键帧。
最低 SDK 版本设置为 API 级别 19。
build.gradle
android {
defaultConfig {
minSdkVersion 19
...
}
...
}
可以在 this GitHub gist 中找到完整的实现。
要按预期执行此操作,您需要将 android:clipChildren="false"
添加到根 ViewGroup
中,在您的情况下,在布局 activity_main_drawer_closed.xml
中是 ConstaintLayout
。当然,这种解决方案仅适用于您的视图在视口之外的情况。
我不知道为什么这种行为因 Android 的版本而异。理论上,从 Android Marshmallow 开始,当您开始场景转换时,根视图因 TransitionManager
和重绘而变得无效。
这是 Java Android 应用程序中的一个问题,在 MainActivity 中有一个非常简单的自定义可拖动抽屉。
这是它在 Android 10(API 级别 29)模拟器上运行时的行为,这是预期的行为。
但问题是,当它在Android L (API level 21) 模拟器上运行时,它的行为出乎意料如下:
在动画期间,UI 组件不可见。但是当应用程序进入后台并返回时,它们就会变得可见。
应用程序的实现细节:
为了检测滑动/拖动触摸手势,使用了GestureDetectorCompat
。
当检测到滑动手势时,将启动自定义抽屉打开动画。
动画是使用 ConstraintSet
、ConstraintLayout
和 TransitionManager
.
这是触摸手势检测和 TransitionManager 动画的实现。
MainActivity.java
public class MainActivity extends AppCompatActivity {
private boolean mIsDrawerOpened;
private ConstraintLayout mRootConstraintLayout;
private final ConstraintSet mDrawerClosedConstraintSet = new ConstraintSet();
private final ConstraintSet mDrawerOpenedConstraintSet = new ConstraintSet();
private GestureDetectorCompat mGestureDetector;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_drawer_closed);
// Drawer is initially closed
mIsDrawerOpened = false;
mRootConstraintLayout = findViewById(R.id.rootConstraintLayout);
mDrawerClosedConstraintSet.clone(this, R.layout.activity_main_drawer_closed);
mDrawerOpenedConstraintSet.clone(this, R.layout.activity_main_drawer_opened);
mGestureDetector = new GestureDetectorCompat(
getApplicationContext(),
new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
// Drag / Fling gesture detected
// TODO: Recongnize unwanted drag / fling gestures and ignore them.
TransitionManager.beginDelayedTransition(mRootConstraintLayout);
// Drawer is closed?
if(!mIsDrawerOpened) {
// Open the drawer
mDrawerOpenedConstraintSet.applyTo(mRootConstraintLayout);
mIsDrawerOpened = true;
}
return true;
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
// Single tap detected
// TODO: If user has tapped on the drawer, do not close it.
TransitionManager.beginDelayedTransition(mRootConstraintLayout);
// Drawer is opened?
if(mIsDrawerOpened) {
// Close the drawer
mDrawerClosedConstraintSet.applyTo(mRootConstraintLayout);
mIsDrawerOpened = false;
}
return true;
}
@Override
public boolean onDown(MotionEvent e) {
return true;
}
}
);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
mGestureDetector.onTouchEvent(event);
return super.onTouchEvent(event);
}
}
这是关闭抽屉的布局XML。
res/layout/activity_main_drawer_closed.xml
<ConstraintLayout
android:id="@+id/rootConstraintLayout">
<ConstraintLayout
android:id="@+id/drawerConstraintLayout"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
<!-- Constraint start (left) of drawer to end (right) of parent (drawer is outside the parent) -->
app:layout_constraintStart_toEndOf="parent"
... >
<Button
android:id="@+id/button1"
android:text="1"
... />
<Button
android:id="@+id/button2"
android:text="2"
... />
</ConstraintLayout>
<ImageView
android:id="@+id/notch"
android:src="@drawable/drawer_notch"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@id/drawerConstraintLayout"
... />
</ConstraintLayout>
这是打开抽屉的布局XML。
res/layout/activity_main_drawer_opened.xml
<ConstraintLayout
android:id="@+id/rootConstraintLayout">
<ConstraintLayout
android:id="@+id/drawerConstraintLayout"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
<!-- Constraint end (right) of drawer to end (right) of parent (drawer is inside the parent) -->
app:layout_constraintEnd_toEndOf="parent"
... >
<Button
android:id="@+id/button1"
android:text="1"
... />
<Button
android:id="@+id/button2"
android:text="2"
... />
</ConstraintLayout>
<ImageView
android:id="@+id/notch"
android:src="@drawable/drawer_notch"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@id/drawerConstraintLayout"
... />
</ConstraintLayout>
来自这 2 个布局的约束集被用作动画的开始和结束关键帧。
最低 SDK 版本设置为 API 级别 19。
build.gradle
android {
defaultConfig {
minSdkVersion 19
...
}
...
}
可以在 this GitHub gist 中找到完整的实现。
要按预期执行此操作,您需要将 android:clipChildren="false"
添加到根 ViewGroup
中,在您的情况下,在布局 activity_main_drawer_closed.xml
中是 ConstaintLayout
。当然,这种解决方案仅适用于您的视图在视口之外的情况。
我不知道为什么这种行为因 Android 的版本而异。理论上,从 Android Marshmallow 开始,当您开始场景转换时,根视图因 TransitionManager
和重绘而变得无效。