无法通过此堆栈跟踪找到崩溃的原因

时间：2016-04-17 13:46:17

标签： android service view stack-trace

我的应用程序的作用是显示通过windowManager.addView()和WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY标记附加的系统覆盖视图。这是通过服务完成的，该服务管理视图可见性和其他一些事情。

但是，我收到了崩溃报告，无法重现这些报告。崩溃堆栈跟踪也与我的应用程序包无关，所以我真的无法解决这个问题的根源。以下是来自不同来源的两个堆栈跟踪，但似乎是相关的：

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.measure(int, int)' on a null object reference
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2388)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2101)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1297)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7011)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:777)
at android.view.Choreographer.doCallbacks(Choreographer.java:590)
at android.view.Choreographer.doFrame(Choreographer.java:560)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:763)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6938)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)


java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getMeasuredWidth()' on a null object reference
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2484)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2181)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1293)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6599)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:800)
at android.view.Choreographer.doCallbacks(Choreographer.java:603)
at android.view.Choreographer.doFrame(Choreographer.java:572)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:786)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5616)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)

似乎OS（ViewRootImpl）导致了这个问题，因为它拥有对我的视图的空引用。所以我无法为此找到解决方法。

似乎自4.4以来所有Android版本都会发生，我的应用程序是Proguarded。这些堆栈跟踪是从Google Play商店崩溃报告中获取的

以下是我将视图附加到系统窗口作为叠加层的方法：

private void attachToSystemWindows(boolean overlayNavigationBar) {
    final WindowManager windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);

    final DisplayMetrics metrics = new DisplayMetrics();
    windowManager.getDefaultDisplay().getMetrics(metrics);

    final boolean isNavBarInBottom = isNavBarInBottom();

    final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
            calculateWindowWidth(overlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight),
            calculateWindowHeight(overlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight),
            0,
            0,
            WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
            0x50728,
            -3
    );
    params.gravity = Gravity.TOP;

    windowManager.addView(this, params);
}

private  boolean isNavBarInBottom() {
    final boolean isLargeDevice = getResources().getConfiguration().smallestScreenWidthDp >= 600;
    final int orientation = getResources().getConfiguration().orientation;

    if (BuildConfig.DEBUG)
        Log.d("MeshView", "Is NavBar in bottom: " + (isLargeDevice || orientation == Configuration.ORIENTATION_PORTRAIT));


    return isLargeDevice || orientation == Configuration.ORIENTATION_PORTRAIT;
}

我的onMeasure方法：

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    if (BuildConfig.DEBUG) Log.d("MeshView", "OnMeasure");
    setMeasuredDimension(
            Math.max(getSuggestedMinimumWidth(), resolveSize(SIZE_MIN_WIDTH, widthMeasureSpec)),
            Math.max(getSuggestedMinimumHeight(), resolveSize(SIZE_MIN_HEIGHT, heightMeasureSpec))
    );
}

5 个答案:

答案 0 :(得分：6)

惊人。我终于找到了问题的根源，但不是原因......我正在用我的观点做点什么：我想根据其方向改变其布局参数，所以我覆盖了onConfigurationChanged()。

然后我用一种讨厌的方式来更新布局参数：分离然后再将它附加到WindowManager，就像这样：

@Override
protected void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);

    final ViewGroup.LayoutParams layoutParams = getLayoutParams();
    if (!(layoutParams instanceof  WindowManager.LayoutParams)) return; //Fix for some ClassCastException in Samsung devices

    final WindowManager windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);

    final DisplayMetrics metrics = new DisplayMetrics();
    windowManager.getDefaultDisplay().getMetrics(metrics);

    final boolean isNavBarInBottom = isNavBarInBottom();

    layoutParams.width = calculateWindowWidth(mOverlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight);
    layoutParams.height = calculateWindowHeight(mOverlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight);
    windowManager.removeView(this);
    windowManager.addView(this, layoutParams);
}

我想在ViewRootImpl类中发生了一些不好的事情，导致它无法正确处理重新附加，从而导致错误。

要解决此问题，只需通过正确的方法：使用WindowManager.updateViewLayout();方法：

@Override
protected void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    if (BuildConfig.DEBUG) Log.d("MeshView", "OnConfigurationChanged");

    final ViewGroup.LayoutParams layoutParams = getLayoutParams();
    if (!(layoutParams instanceof  WindowManager.LayoutParams)) return; //Fix for some ClassCastException in Samsung devices

    final WindowManager windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);

    final DisplayMetrics metrics = new DisplayMetrics();
    windowManager.getDefaultDisplay().getMetrics(metrics);

    final boolean isNavBarInBottom = isNavBarInBottom();

    layoutParams.width = calculateWindowWidth(mOverlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight);
    layoutParams.height = calculateWindowHeight(mOverlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight);
    //windowManager.removeView(this);    DON'T DO THIS
    //windowManager.addView(this, layoutParams);    DON'T DO THIS

    windowManager.updateViewLayout(this, layoutParams); //DO THIS INSTEAD
}

这似乎解决了我的问题。我要感谢这篇文章的作者，它允许我找到这个修复程序）：Android: change LayoutParams of View added by WindowManager

答案 1 :(得分：4)

我认为您在创建params时没有传递正确的标记。

final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
        calculateWindowWidth(overlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight),
        calculateWindowHeight(overlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight),
        0,
        0,
        WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
        0x50728, // problem might be here.
        -3
);

它应该是these values之一。

所以使用类似这样的东西（避免直接传递十六进制值）：

final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
        calculateWindowWidth(overlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight),
        calculateWindowHeight(overlayNavigationBar, isNavBarInBottom, metrics, mNavigationBarHeight),
        0,
        0,
        WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
        WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON, //any flag
        PixelFormat.TRANSLUCENT
);

我还有referenced PixelFormat。

尝试改变这样，看看是否有效。

答案 2 :(得分：4)

在调用ViewRoot.dispatchDetachedFromWindow（）之后通过（windowManager.removeView(this)）删除视图时，

很短，这实际上将viewroot的视图设置为null，这就是为什么在遍历时有NPE的原因

详情： 通过做

  

windowManager.removeView(this);

你基本上在视图的ViewRoot上调用die，然后将MSG_DIE发送到它的处理程序，以便稍后在安全时将其杀死，并将视图添加到WindowManagerGlobal中的mDyingViews列表中。这一切都很好，

然后致电：

  

windowManager.addView(this, layoutParams);

你强制ViewRoot死亡并调用doDie()并连续调用ViewRoot.dispatchDetachedFromWindow()，这会在遍历时将视图设置为null，并且你有NPE。

了解更多信息，请检查WindowManagerGlobal和ViewRootImpl

答案 3 :(得分：0)

Proguard会导致堆栈跟踪问题，尽管应该有一些你自己的代码，尽管需要进一步解读这些代码，所以这让我很难过，通过Gradle关闭Proguard，然后再次运行并查看。

答案 4 :(得分：0)

我在我的应用程序中遇到了同样的问题我使用

解决了问题 
public static final int TYPE_SYSTEM_ALERT;

而不是TYPE_SYSTEM_OVERLAY。我想在调用onMeasure（）之前视图已经被破坏了。这种类型的叠加在某种程度上造成了一个问题，特别是没有命名的pre kit kat设备。

注意：如果您希望覆盖窗口显示在状态栏后面，并且仍然高于所有其他应用程序使用; 

public static final int TYPE_PHONE;

我希望这会有所帮助。

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