WINDOW_SERVICE को एक चर

Question

पर हल नहीं किया जा सकता है, मैंने सोचा था कि WINDOW_SERVICE को android.content.Context में निरंतर परिभाषित किया जाना चाहिए था।

http://developer.android.com/reference/android/content/Context.html#WINDOW_SERVICE

जब मैं कोड की निम्न खंड में इसका इस्तेमाल करते हैं यह कहा कि यह एक चर के रूप में नहीं सुलझाया जा सकता है एक त्रुटि फेंकता है।

Display display = ((WindowManager)getSystemService(WINDOW_SERVICE)).getDefaultDisplay();

यहाँ पूर्ण कोड है:

package com.commonsware.android.skeleton; 

import android.app.Activity; 
import android.content.Context; 
import android.hardware.Camera; 
import android.hardware.Camera.*; 
import android.os.Bundle; 
import android.view.Display; 
import android.view.Surface; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.Window; 
import android.view.WindowManager; 
import android.widget.FrameLayout; 
import java.io.IOException; 
import java.util.List; 

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

public class SimpleBulbActivity extends Activity { 
    private Preview mPreview; 
    FrameLayout preview; 

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

     // Hide the window title. 
     requestWindowFeature(Window.FEATURE_NO_TITLE); 
     setContentView(R.layout.main); 
    } 

    protected void onResume() { 
     super.onResume(); 
     //Setup the FrameLayout with the Camera Preview Screen 
     mPreview = new Preview(this); 
     preview = (FrameLayout)findViewById(R.id.preview); 
     preview.addView(mPreview); 
    } 

} 

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

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

    Preview(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; 
    } 


    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(); 
     Size optimalSize = getOptimalPreviewSize(sizes, w, h); 
     parameters.setPreviewSize(optimalSize.width, optimalSize.height); 

     Display display = ((WindowManager)getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay(); 

     if(display.getRotation() == Surface.ROTATION_0) 
     { 
      parameters.setPreviewSize(h, w);       
      mCamera.setDisplayOrientation(90); 
     } 

     if(display.getRotation() == Surface.ROTATION_90) 
     { 
      parameters.setPreviewSize(w, h);       
     } 

     if(display.getRotation() == Surface.ROTATION_180) 
     { 
      parameters.setPreviewSize(h, w);    
     } 

     if(display.getRotation() == Surface.ROTATION_270) 
     { 
      parameters.setPreviewSize(w, h); 
      mCamera.setDisplayOrientation(180); 
     } 

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

} 

Answer 1

का प्रयास करें ...

Display display = ((WindowManager)getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();