android:activity销毁后,fragment使用控件,空指针
16lz
2021-01-26
fragment和activity绑定,activity退出,然后fragment的接口数据获取到了,使用控件属性,崩溃,按照正常来说,是不会空指针的,报的错是:java.lang.NullPointerException: Attempt to invoke virtual method ...........
我的原意是使用了ButterKnife,他在unbind的时候会把控件属性置空,代码可以在ButterKnife自动生成的文件里看到,文件名是你的使用了ButterKnife的文件+$$ViewBinder, 比如
public class MsgPageFragment$$ViewBinder implements ViewBinder { @Override public void bind(final Finder finder, final T target, Object source) { View view; view = finder.findRequiredView(source, 2131231302, "field 'tvRead'"); target.tvRead = finder.castView(view, 2131231302, "field 'tvRead'"); view = finder.findRequiredView(source, 2131231250, "field 'tvMeetingTime'"); target.tvMeetingTime = finder.castView(view, 2131231250, "field 'tvMeetingTime'"); view = finder.findRequiredView(source, 2131231062, "field 'rlNotifyMeeting' and method 'onViewClicked'"); target.rlNotifyMeeting = finder.castView(view, 2131231062, "field 'rlNotifyMeeting'"); view.setOnClickListener( new butterknife.internal.DebouncingOnClickListener() { @Override public void doClick( android.view.View p0 ) { target.onViewClicked(p0); } }); view = finder.findRequiredView(source, 2131231310, "field 'tvRestaurantTime'"); target.tvRestaurantTime = finder.castView(view, 2131231310, "field 'tvRestaurantTime'"); view = finder.findRequiredView(source, 2131231063, "field 'rlNotifyRestaurant' and method 'onViewClicked'"); target.rlNotifyRestaurant = finder.castView(view, 2131231063, "field 'rlNotifyRestaurant'"); view.setOnClickListener( new butterknife.internal.DebouncingOnClickListener() { @Override public void doClick( android.view.View p0 ) { target.onViewClicked(p0); } }); view = finder.findRequiredView(source, 2131231337, "field 'tvServiceTime'"); target.tvServiceTime = finder.castView(view, 2131231337, "field 'tvServiceTime'"); view = finder.findRequiredView(source, 2131231065, "field 'rlNotifyService' and method 'onViewClicked'"); target.rlNotifyService = finder.castView(view, 2131231065, "field 'rlNotifyService'"); view.setOnClickListener( new butterknife.internal.DebouncingOnClickListener() { @Override public void doClick( android.view.View p0 ) { target.onViewClicked(p0); } }); view = finder.findRequiredView(source, 2131231313, "field 'tvSaleTime'"); target.tvSaleTime = finder.castView(view, 2131231313, "field 'tvSaleTime'"); view = finder.findRequiredView(source, 2131231064, "field 'rlNotifySale' and method 'onViewClicked'"); target.rlNotifySale = finder.castView(view, 2131231064, "field 'rlNotifySale'"); view.setOnClickListener( new butterknife.internal.DebouncingOnClickListener() { @Override public void doClick( android.view.View p0 ) { target.onViewClicked(p0); } }); view = finder.findRequiredView(source, 2131231244, "field 'tvMeetingMsgCount'"); target.tvMeetingMsgCount = finder.castView(view, 2131231244, "field 'tvMeetingMsgCount'"); view = finder.findRequiredView(source, 2131231308, "field 'tvRestaurantMsgCount'"); target.tvRestaurantMsgCount = finder.castView(view, 2131231308, "field 'tvRestaurantMsgCount'"); view = finder.findRequiredView(source, 2131231249, "field 'tvMeetingServiceMsgCount'"); target.tvMeetingServiceMsgCount = finder.castView(view, 2131231249, "field 'tvMeetingServiceMsgCount'"); view = finder.findRequiredView(source, 2131231309, "field 'tvRestaurantServiceCount'"); target.tvRestaurantServiceCount = finder.castView(view, 2131231309, "field 'tvRestaurantServiceCount'"); view = finder.findRequiredView(source, 2131231363, "field 'tvVisitorCount'"); target.tvVisitorCount = finder.castView(view, 2131231363, "field 'tvVisitorCount'"); view = finder.findRequiredView(source, 2131231365, "field 'tvVisitorTime'"); target.tvVisitorTime = finder.castView(view, 2131231365, "field 'tvVisitorTime'"); view = finder.findRequiredView(source, 2131231074, "method 'onViewClicked'"); view.setOnClickListener( new butterknife.internal.DebouncingOnClickListener() { @Override public void doClick( android.view.View p0 ) { target.onViewClicked(p0); } }); } @Override public void unbind(T target) { target.tvRead = null; target.tvMeetingTime = null; target.rlNotifyMeeting = null; target.tvRestaurantTime = null; target.rlNotifyRestaurant = null; target.tvServiceTime = null; target.rlNotifyService = null; target.tvSaleTime = null; target.rlNotifySale = null; target.tvMeetingMsgCount = null; target.tvRestaurantMsgCount = null; target.tvMeetingServiceMsgCount = null; target.tvRestaurantServiceCount = null; target.tvVisitorCount = null; target.tvVisitorTime = null; }}
可以看到,它在unbind把控件都置空了,知道了后解决也很容易了,可以在bind之后赋予一个全局标志位为true,比如
bind = true;
在unbind的前一行或者后一行
bind = false;
然后在获取接口数据的地方加上
if(!bind) {
return;
}
应该看得懂,很简单,这个空指针和activity是否绑定没关系的。
如果你在fragment里使用了activity,或者activity的context,导致空指针才和activity绑定有关系,附上一个activity销毁时,activity和绑定的fragment的生命周期
E/fragment: -- onPause--E/activity: -- onPause--E/fragment: --onStop--E/activity: --onStop--E/fragment: --onDestroyView--E/fragment: --OnDestroy--E/fragment: --OnDetach--E/activity: --onDestroy--
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