图片预览页返回空指针异常

[shucc]

测试手机

Nexus 5

系统版本

6.0.1

错误信息

Process: com.example.previewpicture, PID: 20678
java.lang.RuntimeException: Unable to destroy activity {com.example.previewpicture/com.previewlibrary.GPreviewActivity}: java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3831)
at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3849)
at android.app.ActivityThread.-wrap5(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1398)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
at com.previewlibrary.GPreviewActivity$PhotoPagerAdapter.getCount(GPreviewActivity.java:208)
at android.support.v4.view.ViewPager$MyAccessibilityDelegate.canScroll(ViewPager.java:3103)
at android.support.v4.view.ViewPager$MyAccessibilityDelegate.onInitializeAccessibilityNodeInfo(ViewPager.java:3071)
at android.support.v4.view.AccessibilityDelegateCompat$AccessibilityDelegateJellyBeanImpl$1.onInitializeAccessibilityNodeInfo(AccessibilityDelegateCompat.java:246)
at android.support.v4.view.AccessibilityDelegateCompatJellyBean$1.onInitializeAccessibilityNodeInfo(AccessibilityDelegateCompatJellyBean.java:66)
at android.view.View.onInitializeAccessibilityNodeInfo(View.java:6082)
at android.view.View.createAccessibilityNodeInfoInternal(View.java:6043)
at android.view.View$AccessibilityDelegate.createAccessibilityNodeInfo(View.java:22287)
at android.view.View.createAccessibilityNodeInfo(View.java:6026)
at android.view.accessibility.AccessibilityRecord.setSource(AccessibilityRecord.java:145)
at android.view.accessibility.AccessibilityRecord.setSource(AccessibilityRecord.java:119)
at android.view.View.onInitializeAccessibilityEventInternal(View.java:5980)
at android.view.View$AccessibilityDelegate.onInitializeAccessibilityEvent(View.java:22199)
at android.support.v4.view.AccessibilityDelegateCompatIcs.onInitializeAccessibilityEvent(AccessibilityDelegateCompatIcs.java:97)
at android.support.v4.view.AccessibilityDelegateCompat$AccessibilityDelegateIcsImpl.onInitializeAccessibilityEvent(AccessibilityDelegateCompat.java:192)
at android.support.v4.view.AccessibilityDelegateCompat.onInitializeAccessibilityEvent(AccessibilityDelegateCompat.java:432)
at android.support.v4.view.ViewPager$MyAccessibilityDelegate.onInitializeAccessibilityEvent(ViewPager.java:3054)
at android.support.v4.view.AccessibilityDelegateCompat$AccessibilityDelegateJellyBeanImpl$1.onInitializeAccessibilityEvent(AccessibilityDelegateCompat.java:241)
at android.support.v4.view.AccessibilityDelegateCompatJellyBean$1.onInitializeAccessibilityEvent(AccessibilityDelegateCompatJellyBean.java:61)
at android.view.View.onInitializeAccessibilityEvent(View.java:5966)
at android.view.View.sendAccessibilityEventUncheckedInternal(View.java:5833)
at android.view.View$AccessibilityDelegate.sendAccessibilityEventUnchecked(View.java:22138)
at android.support.v4.view.AccessibilityDelegateCompatIcs.sendAccessibilityEventUnchecked(AccessibilityDelegateCompatIcs.java:122)
at android.support.v4.view.AccessibilityDelegateCompat$AccessibilityDelegateIcsImpl.sendAccessibilityEventUnchecked(AccessibilityDelegateCompat.java:223)
at android.support.v4.view.AccessibilityDelegateCompat.sendAccessibilityEventUnchecked(AccessibilityDelegateCompat.java:371)
at android.support.v4.view.AccessibilityDelegateCompat$AccessibilityDelegateJellyBeanImpl$1.sendAccessibilityEventUnchecked(AccessibilityDelegateCompat.java:268)
at android.support.v4.view.AccessibilityDeleg

目前发现两种修改方法

1.在FragmentPagerAdapter中判断fragments是否为空

private class PhotoPagerAdapter extends FragmentPagerAdapter {

        PhotoPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            return fragments.get(position);
        }

        @Override
        public int getCount() {
            if (null == fragments) {
                return 0;
            }
            return fragments.size();
        }
    }

2.修改onDestory中释放资源顺序

    @Override
    protected void onDestroy() {
        ZoomMediaLoader.getInstance().getLoader().clearMemory(this);
        viewPager.setAdapter(null);
        viewPager.clearOnPageChangeListeners();
        viewPager.removeAllViews();
        fragments.clear();
        imgUrls.clear();
        fragments = null;
        imgUrls = null;
        super.onDestroy();
    }

[yangchaojiang]

不好意思，我没有null判断，clearf方法。我改修一下

[yangchaojiang]

谢谢的你建议，版本1.0.9 好用的话，star一下

[shucc]

是否有考虑修改下开源协议？GPL要求似乎太严苛了点

[yangchaojiang]

苦笑 我看一下

[yangchaojiang]

也是自己进步和改进