下课睡觉 2017-02-10 02:59 采纳率: 16.7%
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nine-patch 加了alpha后就报空指针

我有一张.9图片,但是我想加上透明度,所以就在drawable里创建了个文件:
<?xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android" />

    但是我发现,只要加了alpha后,有的手机可以正常运行,有的手机就会崩掉,报空指针的错误,请问这是为什么?错误如下:

    E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.fc, PID: 2851
              java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.Paint.getAlpha()' on a null object reference
                  at android.graphics.drawable.NinePatchDrawable.draw(NinePatchDrawable.java:250)
                  at android.view.View.getDrawableRenderNode(View.java:15463)
                  at android.view.View.drawBackground(View.java:15412)
                  at android.view.View.draw(View.java:15222)
                  at android.view.View.updateDisplayListIfDirty(View.java:14167)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.view.View.updateDisplayListIfDirty(View.java:14162)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.widget.ListView.drawChild(ListView.java:3396)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.widget.AbsListView.dispatchDraw(AbsListView.java:2603)
                  at android.widget.ListView.dispatchDraw(ListView.java:3391)
                  at android.view.View.draw(View.java:15234)
                  at android.widget.AbsListView.draw(AbsListView.java:4110)
                  at android.view.View.updateDisplayListIfDirty(View.java:14167)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.view.View.draw(View.java:15234)
                  at android.view.View.updateDisplayListIfDirty(View.java:14167)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.view.View.updateDisplayListIfDirty(View.java:14162)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.view.View.updateDisplayListIfDirty(View.java:14162)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.view.View.updateDisplayListIfDirty(View.java:14162)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.view.View.updateDisplayListIfDirty(View.java:14162)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.View.draw(View.java:14959)
                  at android.view.ViewGroup.drawChild(ViewGroup.java:3405)
                  at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3198)
                  at android.view.View.draw(View.java:15234)
                  at android.widget.FrameLayout.draw(FrameLayout.java:598)
                  at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:2650)
                  at android.view.View.updateDisplayListIfDirty(View.java:14167)
                  at android.view.View.getDisplayList(View.java:14189)
                  at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:273)
                  at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:279)
                  at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:318)
                  at android.view.ViewRootImpl.draw(ViewRootImpl.java:2530)
                  at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2352)
                  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1982)
                  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
                  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
                  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
                  at android.view.Choreographer.doCallbacks(Choreographer.java:580)
                at android.view.Choreographer.doF
  • 写回答

1条回答 默认 最新

  • 安妍妍 2017-02-10 15:07
    关注

    有两点需要特别注意下:

    1.最外围的一圈像素必须要么是纯黑色,要么是透明,一点点的半透明的像素都不可以有,比如说99%的黑色或者是1%的投影都不可以有;
    2.文件的后缀名必须是.9.png,不能是.png或者是.9.png.png,这样的命名都会导致编译失败。
    参考链接:https://www.oschina.net/question/565065_66807

    评论

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