在测试环境中使用findViewById（）时返回null？

Question

I have a layout (main_layout) that i inflate in the fragment. Now when i try to access it from test class using the following:

View testLayout=getActivity().findViewById(R.layout.main_layout);

It returns to me null? Can anyone tell me whats the wrong thing i am doing?

Answer 1

I think you make some confusion about View and layout resource. if you want to get layout as View,you can do it like this:

LayoutInflater inflater = getLayoutInflater();
View layout = inflater.inflate(R.layout.main_layout, null);

or if you want to get a view within the layout(make sure you've specified id for it. eg android:id="@+id/textview01"), you can do it like this:

setContentView(R.layout.main_layout);
TextView textView = (TextView) findViewById(R.id.textview01);

you will get the TextView within main_layout.xml

Answer 2

Try using this,

LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.main_layout, container, false);

Answer 3

您应该通过id引用视图，因此应该使用类似R.id.main_layout视图，而不是使用R.layout.main_layout

Answer 4

First set an id to the top-level layout in your main_layout.xml file. For example the id could be @+id/main_layout_wrapper .

Then in your test class search for it using:

View testLayout = getActivity().findViewById(R.id.main_layout_wrapper);

Answer 5

This type of error cause by below points:

1. Are you using same layout in setContentView().
2. You are using same widget id.

So please Check your activity properly and use debug.