在我的 Android 应用程序中,我有一个初始屏幕,我可以在其中进行一些设置和加载。我的应用使用默认的 explode
作为 windowEnterTransition
和 windowExitTransition
和 changeImageTransform
加上 changeBounds
转换设置为 windowSharedElementEnterTransition
和 windowSharedElementExitTransition
。为方便起见,我使用静态方法启动下一个 Activity
,我将当前 Activity
作为 Context
和共享元素传递。代码在本文的第二部分提供。
其中一种情况是没有要加载的内容,因此应用程序几乎立即触发下一个 Activity
。问题是,在这种情况下,应用程序以某种方式莫名其妙地在 ActivityTransitionCoordinator
中崩溃,堆栈在本文的下一部分中给出。内部调试表明,在那里实现的 ViewRootImpl
为 null,并且没有进行 null 检查,因此调用 viewRoot.setPausedForTransition(false)
会抛出一个 NullPointerException
。你可以在下面的代码中找到这个不吉利的地方。
为了关注这个失败的场景,让我们假设一个决定没有什么可以加载并且下一个 Activity
应该立即启动的逻辑非常简单,它可以简化为开始上述 Activity 。
如果在 onCreate()
、onResume()
或 中调用第二个
方法。我什至尝试在通过调用 Activity
的开始没有区别onEnterAnimationComplete()getWindow().getSharedElementEnterTransition()
和 getWindow().getEnterTransition()
获得的 Transition 上添加一个监听器,以允许启动下一个 Activity
转换完成时。给定的 Transitions
不为空,但应用程序永远不会进入附加监听器的方法。
我现在使用的解决方法是安排一个 Runnable
来延迟调用下一个 Activity
。
我想知道这是否是 Android
(更具体地说是 SupportLibrary
)问题,或者我错过了什么。有没有人遇到过类似的问题?
堆栈跟踪:
08-12 00:35:32.550 26453-26453/com.faver.mkoslacz.faverdemo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.faver.mkoslacz.faverdemo, PID: 26453
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.ViewRootImpl.setPausedForTransition(boolean)' on a null object reference
at android.app.ActivityTransitionCoordinator.startInputWhenTransitionsComplete(ActivityTransitionCoordinator.java:897)
at android.app.ActivityTransitionCoordinator.viewsTransitionComplete(ActivityTransitionCoordinator.java:885)
at android.app.ExitTransitionCoordinator.getExitTransition(ExitTransitionCoordinator.java:318)
at android.app.ExitTransitionCoordinator.beginTransitions(ExitTransitionCoordinator.java:365)
at android.app.ExitTransitionCoordinator.-wrap0(ExitTransitionCoordinator.java)
at android.app.ExitTransitionCoordinator$4.run(ExitTransitionCoordinator.java:216)
at android.app.ActivityTransitionCoordinator.startTransition(ActivityTransitionCoordinator.java:773)
at android.app.ExitTransitionCoordinator.startExit(ExitTransitionCoordinator.java:213)
at android.app.ActivityTransitionState.startExitOutTransition(ActivityTransitionState.java:317)
at android.app.Activity.cancelInputsAndStartExitTransition(Activity.java:3960)
at android.app.Activity.startActivityForResult(Activity.java:3936)
at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:48)
at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:75)
at android.app.Activity.startActivity(Activity.java:4196)
at com.faver.mkoslacz.faverdemo.activity.AuthorizationActivity.startWithTransiton(AuthorizationActivity.java:45)
at com.faver.mkoslacz.faverdemo.activity.SplashActivity.onEnterAnimationComplete(SplashActivity.java:27)
at android.app.Activity.dispatchEnterAnimationComplete(Activity.java:5852)
at android.app.ActivityThread.handleEnterAnimationComplete(ActivityThread.java:2668)
at android.app.ActivityThread.-wrap10(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1558)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
ActivityTransitionAnimator
中的代码失败:
private void startInputWhenTransitionsComplete() {
if (mViewsTransitionComplete && mSharedElementTransitionComplete) {
final View decor = getDecor();
if (decor != null) {
final ViewRootImpl viewRoot = decor.getViewRootImpl(); // it's null
viewRoot.setPausedForTransition(false); // crashes here
}
onTransitionsComplete();
}
}
启动下一个Activity
的方法:
public static void startWithTransiton(Activity activity, android.view.View logo) {
Intent intent = new Intent(activity, AuthorizationActivity.class);
ActivityOptionsCompat options = ActivityOptionsCompat
.makeSceneTransitionAnimation(
activity,
logo,
activity.getString(R.string.logoTransfer));
activity.startActivity(intent, options.toBundle());
}
splash Activity
内容(简化):
public class SplashActivity extends AppCompatActivity {
private static final String TAG = "SplashActivity";
private View logo;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
logo = findViewById(R.id.logo);
// AuthorizationActivity.startWithTransiton(this, logo); // will fail
new Handler().postDelayed(() -> {
AuthorizationActivity.startWithTransiton(this, logo); // executes flawlessly
}, 300);
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
Transition sharedElementEnterTransition = getWindow().getSharedElementEnterTransition();
if (sharedElementEnterTransition != null) {
sharedElementEnterTransition.addListener(new Transition.TransitionListener() {
@Override
public void onTransitionStart(Transition transition) {
Log.d(TAG, "onTransitionStart: never executes");
}
@Override
public void onTransitionEnd(Transition transition) {
Log.d(TAG, "onTransitionEnd: never executes");
}
@Override
public void onTransitionCancel(Transition transition) {
Log.d(TAG, "onTransitionCancel: never executes");
}
@Override
public void onTransitionPause(Transition transition) {
Log.d(TAG, "onTransitionPause: never executes");
}
@Override
public void onTransitionResume(Transition transition) {
Log.d(TAG, "onTransitionResume: never executes");
}
});
}
Transition enterTransition = getWindow().getEnterTransition();
if (enterTransition != null) {
enterTransition.addListener(new Transition.TransitionListener() {
@Override
public void onTransitionStart(Transition transition) {
Log.d(TAG, "onTransitionStart: never executes");
}
@Override
public void onTransitionEnd(Transition transition) {
Log.d(TAG, "onTransitionEnd: never executes");
}
@Override
public void onTransitionCancel(Transition transition) {
Log.d(TAG, "onTransitionCancel: never executes");
}
@Override
public void onTransitionPause(Transition transition) {
Log.d(TAG, "onTransitionPause: never executes");
}
@Override
public void onTransitionResume(Transition transition) {
Log.d(TAG, "onTransitionResume: never executes");
}
});
}
}
}
@Override
protected void onResume() {
super.onResume();
// AuthorizationActivity.startWithTransiton(this, logo); // will fail
}
@Override
public void onEnterAnimationComplete() {
super.onEnterAnimationComplete();
// AuthorizationActivity.startWithTransiton(this, logo); // will fail
}
}
最佳答案
我在使用 Explode Activity 转换时也遇到了同样的问题,我发现这段代码在 Lollipop 版本中运行正常,但在 Lollipop 之上崩溃了。 即使我找不到崩溃的原因。但我用另一种方式解决了它。只需延迟 Activity 转换。我在下面给出了我的代码
public class SplashActivity extends AppCompatActivity {
final Handler handler = new Handler();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
handler.postDelayed(new Runnable() {
@Override
public void run() {
navigate();
}
},500);
}
private void navigate() {
ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(this);
Intent intent = new Intent(SplashActivity.this, MainActivity.class);
startActivity(intent, options.toBundle());
}}
添加后在所有版本中正常工作。
关于java - ViewRootImpl.setPausedForTransition(boolean) NullPointerException 在 ActivityTransitionCoordinator 中转换到其他 Activity 调用过早,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38932405/