解决java.lang.IllegalStateException: Fragment not attached to Activity

最新推荐文章于 2024-11-03 23:03:34 发布

转载最新推荐文章于 2024-11-03 23:03:34 发布 · 3.6k 阅读

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本文介绍了解决Android应用中由于Volley请求导致Fragment内存泄漏的问题。通过检查Activity是否有效避免内存泄漏，并确保在错误回调中使用isAdded()方法来判断Fragment是否仍然附加在Activity上。

转载至：http://stackoverflow.com/questions/28672883/java-lang-illegalstateexception-fragment-not-attached-to-activity

This error happens due to the combined effect of two factors:

The HTTP request, when complete, invokes either onResponse() or onError() (which work on the main thread) without knowing whether the Activity is still in the foreground or not. If the Activity is gone (the user navigated elsewhere), getActivity() returns null.
The Volley Response is expressed as an anonymous inner class, which implicitly holds a strong reference to the outer Activity class. This results in a classic memory leak.
To solve this problem, you should always do:

Activity activity = getActivity();
if(activity != null){

    // etc ...

}

and also, use isAdded() in the onError() method as well:

@Override
public void onError(VolleyError error) {

    Activity activity = getActivity(); 
    if(activity != null && isAdded())
        mProgressDialog.setVisibility(View.GONE);
        if (error instanceof NoConnectionError) {
           String errormsg = getResources().getString(R.string.no_internet_error_msg);
           Toast.makeText(activity, errormsg, Toast.LENGTH_LONG).show();
        }
    }
}