扩展类时膨胀时出错

class android java xml surfaceview

2022-08-31 06:31:58

我正在尝试创建一个扩展的自定义视图。这是我的类定义文件GhostSurfaceCameraViewSurfaceView

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();
    }
}

这是我的鬼景屏幕.xml：

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

现在在我做的活动中：

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

调用时，将引发异常：setContentView()

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

谁能告诉我为什么我得到这个错误？谢谢。

答案 1

我想我弄清楚了为什么这不起作用。我只为一个参数“context”的情况提供了一个构造函数，而我应该为两个参数'Context，AttributeSet'提供一个构造函数。我还需要为构造函数提供公共访问权限。这是我的修复：

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();
        }

答案 2

@Tim - 两个构造函数都不是必需的，只有构造函数是必需的。在浪费了几个小时和几个小时的时间之后，我以痛苦的方式发现了这一点。ViewClassName(Context context, AttributeSet attrs )

我对 Android 开发非常陌生，但我在这里做了一个疯狂的猜测，这可能是由于我们在 XML 文件中添加了自定义类，因此我们在 XML 中为其设置了几个属性，这些属性需要在实例化时进行处理。不过，比我知识渊博的人将能够更清楚地了解这个问题。View