How to capture AR view

i want to capture ar view in my app.

i have been read this thread:https://developer.vuforia.com/forum/faq/android-how-can-i-capture-ar-view

and i also do what AlessandroB say on this thread:

https://developer.vuforia.com/forum/qcar-api/how-make-screenshot

i try on my project, it didn't show anyerror. but i also didn't got my screenshot.

i didn't see any error in LogCat. i think i must show my code to you, so this my code on ImageTargetsRendered.java

public boolean mTakeScreenshot = false;
    public void takeScreenshot() {
      mTakeScreenshot = true;    
    }
    
    public void onDrawFrame(GL10 gl)
    {
        if (!mIsActive)
            return;
 
        // Update render view (projection matrix and viewport) if needed:
            //mActivity.updateRenderView();
 
        // Call our native function to render content
        renderFrame();
         
        // make sure the OpenGL rendering is finalized
        GLES20.glFinish();
        
        
        if (mTakeScreenshot==true) {
            saveScreenShot(0, 0, mViewWidth, mViewHeight, "test.png");
            mTakeScreenshot = false;
        }
    }

that the last part from your code and i add takeScreenshot method that i call in ImageTargets.java with this code:

public void takeScreenshot2(View view) {
        ImageTargetsRenderer ambil = new ImageTargetsRenderer();
        button1.setVisibility(View.INVISIBLE);
        ambil.takeScreenshot();
        button1.setVisibility(View.VISIBLE);
      }

there is any wrong code that i add??