Question

我正在尝试创建一个自定义SurfaceView，用于在另一个当前显示Camera实时输出的SurfaceView上绘制菜单/或其他组件。

因此我创建了一个扩展SurfaceView的类“OverlayOfSurfaceView”，见下文：

  package com.net.app.barcode;

    import com.net.app.R;

    import android.content.Context;
    import android.graphics.Canvas;
    import android.util.AttributeSet;
    import android.view.SurfaceHolder;
    import android.view.SurfaceView;

    public class OverlayOfSurfaceView extends SurfaceView  implements
SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Context context;
    private LinearLayout linearMenu = null; 
    public OverlayOfSurfaceView(Context context, AttributeSet attr) {
        super(context,attr);
        this.context = context;
        // TODO Auto-generated constructor stub
        mHolder = getHolder();
        mHolder.addCallback(this);
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        linearMenu = (LinearLayout) this.findViewById(R.layout.barcode_scanner_overlay_menu);
        setFocusable(true);
        requestFocus();


    }


    @Override
    public void onDraw(Canvas canvas) {

    drawGuidance(canvas);
    }

    public void drawGuidance(Canvas canvas) {

         Log.w(this.getClass().getName(),"drawGuidance(Canvas canvas)");
        Paint paintRed = new Paint();
        paintRed.setStyle(Paint.Style.STROKE);
        paintRed.setStrokeWidth(6f);
        paintRed.setAntiAlias(true);
        paintRed.setColor(Color.BLUE);
        // drawMiddleline
        canvas.drawLine( this.getHeight()/2,0,this.getWidth(),this.getHeight()/2 , paintRed);

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
         Log.w(this.getClass().getName(),"surface created");
        // TODO Auto-generated method stub
        setWillNotDraw(false);

    }
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
         Log.w(this.getClass().getName(),"surface changed");
        // TODO Auto-generated method stub
        // If your preview can change or rotate, take care of those events
                    // here.
    }



    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
         Log.w(this.getClass().getName(),"surface destroyed");
        // TODO Auto-generated method stub
        // empty. Take care of releasing resources here 
    }

}//end class

OverlayOfSurfaceView的布局，见下文：

   <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/LayoutForPreview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:screenOrientation="portrait"
    android:scaleType="fitXY" >


     <SurfaceView
        android:id="@+id/surfaceViewBarcodeScanner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scaleType="fitXY"
         />

     <com.yourmarketnet.yourmarketapp.barcode.OverlayOfSurfaceView
        android:id="@+id/overlay"
        android:layout_width="match_parent"
       android:layout_height="wrap_content"
        android:scaleType="fitXY" />


</FrameLayout>

最后下面是onCreate（）方法的相关片段，在Activity（）中我实例化了自定义SurfaceView，名为OverlayOfSurfaceView：

  public class ScanVinFromBarcodeActivity extends Activity {

    //irrelevant parts not included in this post

    // onCreate method, instantiates layouts & surfaceView used for video preview
        @Override
            public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_barcode_vin_scanner);
        Log.d("ClassScanViewBarcodeActivity", "onCreate ");

        // create surfaceView for previewing of camera image
        FrameLayoutBarcodeScanner = (FrameLayout) findViewById(R.id.LayoutForPreview);  
        surfaceViewBarcodeScanner = (SurfaceView) findViewById(R.id.surfaceViewBarcodeScanner);

        surfaceViewLayOver = (OverlayOfSurfaceView) findViewById(R.id.overlay);
        //make the background transparent so the user can see surfaceViewBarcodeScanner behind this SurfaceView
        surfaceViewLayOver.setAlpha(0);
        //pass overlay to layout 
        FrameLayoutBarcodeScanner.addView(surfaceViewLayOver);

        globalContext  = this.getApplicationContext();
        initializeGlobalCamera();

//removed code irrelevant to this post 

}//end onCreate


    //irrelevant parts not included in this post
    }//end Activity class

来自日志的实际错误摘录：

最后下面是onCreate（）方法的相关片段，在我实例化Class的Activity中：以下是导致令人讨厌的崩溃的运行时异常：

04-04 18:05:40.833: E/AndroidRuntime(15123): java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.net.app/com.net.app.barcode.ScanVinFromBarcodeActivity}: 
android.view.InflateException: Binary XML file line #18: 
Error inflating class com.net.app.barcode.OverlayOfSurfaceView
04-04 18:05:40.833: E/AndroidRuntime(15123): Caused by: android.view.InflateException: 
Binary XML file line #18: Error inflating class com.net.app.barcode.OverlayOfSurfaceView

04-04 18:05:40.833: E/AndroidRuntime(15123): 
Caused by: java.lang.NoSuchMethodException: <init> 
[class android.content.Context, interface android.util.AttributeSet]

请善意为此问题提供有效的解决方案。感谢

Answer 1

您需要让某些构造函数能够通过XML实例化您的自定义视图。

http://developer.android.com/training/custom-views/create-view.html#subclassview

我不想提供有效的解决方案。

自定义SurfaceView抛出java.lang.RuntimeException＆amp; java.lang.NoSuchMethodException

1 个答案: