이 코드가 Android에서 이미지를 표시하지 않는 이유를 알아낼 수 없습니다.

Question

TicTacToeLib 용 리소스의 샘플 코드와 Android 애플리케이션이라는 제목의 비트 맵을 표시하는 방법에 대한 예제를 매우 자세히 검토하고 있습니다. 개발. 나는 그들이하는 일과 똑같은 일을하고 있습니다. 유일한 차이점은 뷰 대신에 SurfaceView를 사용하고 있다는 것입니다. 아무도 내가 뭘 잘못하고 있다고 말할 수 있습니까? 최종 목표는 수동으로 카메라의 미리보기 이미지를 표시하고 이미지를 위에 표시하는 것입니다.

죄송합니다. 문제가 무엇인지 포함하는 것을 잊었습니다. onDraw 메서드는 지금까지 호출되지 않습니다. 무효화 메소드가 호출해야한다는 인상 아래에있었습니다. 둘째로 lockCanvas() 메서드가 NULL 캔버스를 반환합니다. SurfaceHolder에서 PUSH_BUFFER 상수를 사용하지 않도록 코드를 수정 한 후에도 (이 수정 코드를 편집했습니다).

package com.test.combine; 

import android.content.res.XmlResourceParser; 
import android.app.Activity; 
import android.content.Context; 
import android.hardware.Camera; 
import android.hardware.Camera.Size; 
import android.os.Bundle; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.Window; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
import android.graphics.Paint; 
import android.util.AttributeSet; 
import java.io.IOException; 
import android.util.Log; 
import java.util.List; 

public class CombineTestActivity extends Activity 
{ 
private Preview mPreview; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    // Hide the window title. 
    requestWindowFeature(Window.FEATURE_NO_TITLE); 

    // Create our Preview view and set it as the content of our activity. 
    mPreview = new Preview(this); 
    setContentView(mPreview); 
} 

} 

// ---------------------------------------------------------------------- 

class Preview extends SurfaceView implements SurfaceHolder.Callback { 
private SurfaceHolder mHolder; 
private Camera mCamera; 
private Paint mPaint; 
private Canvas canvas; 
private Bitmap currentprev; 
private Picture mPicture; 

private Camera.PreviewCallback mPrevCallback = new Camera.PreviewCallback() 
{ 
     public void onPreviewFrame(byte[] data, Camera Cam) { 
       Log.d("CombineTestActivity", "Preview registered"); 
       Log.d("CombineTestActivity", "Data length = " 
         + data.length); 
       // currentprev = BitmapFactory.decodeByteArray(data, 0, 
       //  data.length); 

       currentprev = BitmapFactory.decodeResource(getResources(), 
        R.drawable.creature00); 
       if(currentprev == null) 
        Log.d("CombineTestActivity", "currentprev is null"); 

       Log.d("CombineTestActivity", "Preview Finished"); 
       invalidate(); 
     } 
}; 

private OnTouchListener mCorkyListener = new OnTouchListener() { 
     public boolean onTouch(View v, MotionEvent me) { 
       Log.d("CombineTestActivity", "touch registered"); 
       mCamera.takePicture(null, null, mPicCallback); 
       return false; 
     } 
}; 

private Camera.PictureCallback mPicCallback = new Camera.PictureCallback() { 
     public void onPictureTaken(byte[] data, Camera mCamera) { 

       Log.d("CombineTestActivity", "picture method run"); 
     } 
}; 

Preview(Context context) { 
    super(context); 

    // Install a SurfaceHolder.Callback so we get notified when the 
    // underlying surface is created and destroyed. 
mPicture = new Picture(); 
    mHolder = getHolder(); 
    mHolder.addCallback(this); 
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_NORMAL); 
    mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); 
    canvas = mHolder.lockCanvas(); 
    if(canvas==null) 
     Log.d("CombineTestActivity", "canvas is null in constructor"); 

this.setOnTouchListener(mCorkyListener); 

invalidate(); 

} 

@Override 
protected void onDraw(Canvas mCanvas) { 

     if(mCanvas == null) 
       Log.e("CombineTestActivity", "canvas is null"); 
     if(currentprev == null) { 
       Log.e("CombineTestActivity", "currentprev is null"); 
       return; 
     } 

     mCanvas.drawBitmap(currentprev, 0.0f, 0.0f, mPaint); 

     Log.d("CombineTestActivity", "exiting onDraw"); 

} 


public void surfaceCreated(SurfaceHolder holder) { 
    // The Surface has been created, acquire the camera and tell it where 
    // to draw. 

    mCamera = Camera.open(); 
    mCamera.setPreviewCallback(mPrevCallback); 

    /*   
    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; 
} 

private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) { 
    final double ASPECT_TOLERANCE = 0.05; 
    double targetRatio = (double) w/h; 
    if (sizes == null) return null; 

    Size optimalSize = null; 
    double minDiff = Double.MAX_VALUE; 

    int targetHeight = h; 

    // Try to find an size match aspect ratio and size 
    for (Size size : sizes) { 
     double ratio = (double) size.width/size.height; 
     if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue; 
     if (Math.abs(size.height - targetHeight) < minDiff) { 
      optimalSize = size; 
      minDiff = Math.abs(size.height - targetHeight); 
     } 
    } 

    // Cannot find the one match the aspect ratio, ignore the requirement 
    if (optimalSize == null) { 
     minDiff = Double.MAX_VALUE; 
     for (Size size : sizes) { 
      if (Math.abs(size.height - targetHeight) < minDiff) { 
       optimalSize = size; 
       minDiff = Math.abs(size.height - targetHeight); 
      } 
     } 
    } 
    return optimalSize; 
} 

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(); 

    List<Size> sizes = parameters.getSupportedPreviewSizes(); 
    if(sizes.isEmpty()) 
     Log.d("CameraTestActivity", "sizes null"); 
    else 
     Log.d("CameraTestActivity", "sizes not null"); 

    Size optimalSize = getOptimalPreviewSize(sizes, w, h); 
    if(optimalSize == null) 
     Log.d("CameraTestActivity", "optimalSize null"); 
    else 
     Log.d("CameraTestActivity", "optimalSize not null"); 


    parameters.setPreviewSize(optimalSize.width, optimalSize.height); 

if(parameters == null) 
    Log.d("CameraTestActivity", "parameters null"); 
else 
    Log.d("CameraTestActivity", "parameters not null"); 

    mCamera.setParameters(parameters); 
    mCamera.startPreview(); 
} 


} 

Answer 1

분명히 해결책을 찾았습니다. SurfaceView는 View에서 상속 받지만 View처럼 onDraw를 호출하지 않습니다. lockCanvas가 작동하지 않는 이유는 무엇입니까?