无法在 Android Studio 中找到 getExternalFilesDir() 函数的上下文

Question

So, I am trying to write text to a file in Android Studio. I have the following code:

public void sampleFunction() {
    File file = new File(getExternalFilesDir(null), "sample-file.txt");
}

The issue is that the method getExternalFilesDir(null) cannot be resolved. After doing some research I have noted that I need to provide the Context class. Such as:

public void sampleFunction(Context c) {
    File file = new File(c.getExternalFilesDir(null), "equation_history.xml");
}

And when I called sampleFunction, I would simply pass in the current Context:

sampleFunction(this);

This normally would work, however, I need to call this function inside a setOnClickListener function for a Button. For example:

Button b_go = findViewById(R.id.b_go);
b_go.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        Functions.sampleFunction(this);
    }
});

So the return value for this is android.view.View.OnClickListener rather than android.content.Context .

How might I get around this? Any advice would be greatly appreciated.

Answer 1

Instead of passing "this" as an argument try calling getApplicationContext() or if you are in fragment just call getActivity().

Answer 2

What is often done is that a Context myContext variable is declared in the class, then onCreate, you populate it with myContext = this; Then, in any listener or Async Task, you can use myContext.getExternalFilesDir(null)

Answer 3

File storageDir = getActivity().getExternalFilesDir(Environment.DIRECTORY_PICTURES);