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java – Error inflating when extending a class

Posted by: admin March 10, 2020 Leave a comment

Questions:

I’m trying to create a custom view GhostSurfaceCameraView that extends SurfaceView. Here’s my class definition file

GhostSurfaceCameraView.java:

public class GhostSurfaceCameraView extends SurfaceView implements SurfaceHolder.Callback {
    SurfaceHolder mHolder;
    Camera mCamera;

    GhostSurfaceCameraView(Context context) {
        super(context);

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, acquire the camera and tell it where to draw.
        mCamera = Camera.open();
        try {
            mCamera.setPreviewDisplay(holder);
        } catch (IOException exception) {
            mCamera.release();
            mCamera = null;
            // TODO: add more exception handling logic here
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // Surface will be destroyed when we return, so stop the preview.
        // Because the CameraDevice object is not a shared resource, it's very
        // important to release it when the activity is paused.
        mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
    }   

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // Now that the size is known, set up the camera parameters and begin
        // the preview.
        Camera.Parameters parameters = mCamera.getParameters();
        parameters.setPreviewSize(w, h);
        parameters.set("orientation", "portrait");
        // parameters.setRotation(90); // API 5+
        mCamera.setParameters(parameters);
        mCamera.startPreview();
    }
}

And this is in my ghostviewscreen.xml:

<com.alpenglow.androcap.GhostSurfaceCameraView android:id="@+id/ghostview_cameraview"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"/>

Now in the activity I made:

protected void onCreate(Bundle savedInstanceState) {
    try {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.ghostviewscreen);
    }
}

When setContentView() gets called, an exception is thrown:

Binary XML file 09-17 22:47:01.958: ERROR/ERROR(337):
ERROR IN CODE:
android.view.InflateException: Binary
XML file line #14: Error inflating
class
com.alpenglow.androcap.GhostSurfaceCameraView

Can anyone tell me why I get this error? Thanks.

How to&Answers:

I think I figured out why this wasn’t working. I was only providing a constructor for the case of one parameter ‘context’ when I should have provided a constructor for the two parameter ‘Context, AttributeSet’ case. I also needed to give the constructor(s) public access. Here’s my fix:

public class GhostSurfaceCameraView extends SurfaceView implements SurfaceHolder.Callback {
        SurfaceHolder mHolder;
        Camera mCamera;

        public GhostSurfaceCameraView(Context context)
        {
            super(context);
            init();
        }
        public GhostSurfaceCameraView(Context context, AttributeSet attrs)
        {
            super(context, attrs);
            init();
        }
        public GhostSurfaceCameraView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
            init();
        }

Answer:

@Tim – Both the constructors are not required, only the ViewClassName(Context context, AttributeSet attrs ) constructor is necessary. I found this out the painful way, after hours and hours of wasted time.

I am very new to Android development, but I am making a wild guess here, that it maybe due to the fact that since we are adding the custom View class in the XML file, we are setting several attributes to it in the XML, which needs to be processed at the time of instantiation. Someone far more knowledgeable than me will be able to shed clearer light on this matter though.

Answer:

Another possible cause of the “Error inflating class” message could be misspelling the full package name where it’s specified in XML:

<com.alpenglow.androcap.GhostSurfaceCameraView android:id="@+id/ghostview_cameraview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"/>

Opening your layout XML file in the Eclipse XML editor should highlight this problem.

Answer:

It’s important to write full class path in the xml.
I got ‘Error inflating class’ when only subclass’s name was written in.

Answer:

I had this error plaguing me for the past few hours. Turns out, I had added the custom view lib as a module in Android Studio, but I had neglected to add it as a dependency in app’s build.gradle.

dependencies {
    ...
    compile project(':gifview')
}

Answer:

fwiw, I received this error due to some custom initialization within the constructor attempting to access a null object.

Answer:

I had the same problem extending a TextEdit. For me the mistake was I did non add “public” to the constructor. In my case it works even if I define only one constructor, the one with arguments Context and AttributeSet. The wired thing is that the bug reveals itself only when I build an APK (singed or not) and I transfer it to the devices. When the application is run via AndroidStudio -> RunApp on a USB connected device the app works.

Answer:

in my case I added such cyclic resource:

<drawable name="above_shadow">@drawable/above_shadow</drawable>

then changed to

<drawable name="some_name">@drawable/other_name</drawable>

and it worked

Answer:

In my case, I copied my class from somewhere else and didn’t notice right away that it was an abstract class. You can’t inflate abstract classes.

Answer:

The thing to understand here is that:

The constructor ViewClassName(Context context, AttributeSet attrs ) is called when inflating the customView via xml.
You see you are not using the new keyword to instantiate your object i.e. you are not doing new GhostSurfaceCameraView(). Doing this you are calling the first constructor i.e. public View (Context context).

Whereas when inflating view from XML, i.e. when using setContentView(R.layout.ghostviewscreen); or using findViewById, you, NO, not you!, the android system calls the ViewClassName(Context context, AttributeSet attrs ) constructor.

This is clear when reading the documentation : “Constructor that is called when inflating a view from XML.” See: https://developer.android.com/reference/android/view/View.html#View(android.content.Context,%20android.util.AttributeSet)

Hence, never forget basic polymorphism and never forget reading through the documentation. It saves a ton of headache.