收到错误："java.lang.IllegalStateException: Activity has been destroyed"时通知数据集已更改视图寻呼器适配器

Question

我正在调用notifydatasetchanged（）以查看pager apapter in Activitive ractivityResult（...）方法中的PAGER适配器。我面临的"致命例外：java.lang.IllegalStateException：活动已被破坏"仅在某些设备中。下面是堆栈跟踪。

Fatal Exception: java.lang.IllegalStateException: Activity has been destroyed
   at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1515)
   at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:638)
   at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:621)
   at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:139)
   at android.support.v4.view.ViewPager.dataSetChanged(ViewPager.java:1003)
   at android.support.v4.view.ViewPager$PagerObserver.onChanged(ViewPager.java:2996)
   at android.support.v4.view.PagerAdapter.notifyDataSetChanged(PagerAdapter.java:279)
   at com.demo.activities.ActivityMain$1.run(ActivityMain.java:180)
   at android.os.Handler.handleCallback(Handler.java:751)
   at android.os.Handler.dispatchMessage(Handler.java:95)
   at android.os.Looper.loop(Looper.java:154)
   at android.app.ActivityThread.main(ActivityThread.java:6351)
   at java.lang.reflect.Method.invoke(Method.java)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:896)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:786)

View Pager仅包含两个片段（V4）。我正在在以下代码中进行通知达塔式的行中遇到错误。

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data); 
    if (resultCode == 100) {
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mViewPager.getAdapter().notifyDataSetChanged();
            }
        }, 1000);
    }}

我是否需要执行任何内部运行方法，以检查活动是否仍然存在以避免此例外？

Answer 1

每当您访问延迟或回调中的实例变量或上下文时，您应该首先检查其存在。

活动

Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            if(!isFinishing())
            mViewPager.getAdapter().notifyDataSetChanged();
        }
    }, 1000);

for Fragment

Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            if(isAdded())
            mViewPager.getAdapter().notifyDataSetChanged();
        }
    }, 1000);