问获得带有新API 21的摄像机预览

EN

import android.content.Context;  
import android.hardware.Camera;  
import android.hardware.Camera.AutoFocusCallback;  
import android.hardware.Camera.PreviewCallback;  
import android.util.Log;  
import android.view.SurfaceHolder;  
import android.view.SurfaceView;
import java.io.IOException;
public class CameraPreview extends SurfaceView implements     SurfaceHolder.Callback   
{  

private SurfaceHolder mHolder;  
private Camera mCamera;  
private PreviewCallback previewCallback;  
private AutoFocusCallback autoFocusCallback;  


public CameraPreview(Context context, Camera camera,PreviewCallback previewCb,AutoFocusCallback autoFocusCb)   
{  
    super(context);  
    mCamera = camera;  
    previewCallback = previewCb;  
    autoFocusCallback = autoFocusCb;  

    // Set camera to continuous focus if supported, otherwise use  
    // software auto-focus. Only works for API level >=9.  

    // Camera.Parameters parameters = camera.getParameters();  
    // for (String f : parameters.getSupportedFocusModes()) {  
    //     if (f == Parameters.FOCUS_MODE_CONTINUOUS_PICTURE) {  
    //         mCamera.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);  
    //         autoFocusCallback = null;  
    //         break;  
    //     }  
    // }  

    // Install a SurfaceHolder.Callback so we get notified when the  
    // underlying surface is created and destroyed.  

    mHolder = getHolder();  
    mHolder.addCallback(this);  

    // deprecated setting, but required on Android versions prior to 3.0  
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);  
}   

public void surfaceCreated(SurfaceHolder holder) {  
    // The Surface has been created, now tell the camera where to draw the preview.  
    try   
    {  
        mCamera.setPreviewDisplay(holder);  
    } catch (IOException e) {  
        Log.d("DBG", "Error setting camera preview: " + e.getMessage());  
    }  
}  

public void surfaceDestroyed(SurfaceHolder holder)   
{  
    // Camera preview released in activity  
}  

public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {  
    /* 
     * If your preview can change or rotate, take care of those events here. 
     * Make sure to stop the preview before resizing or reformatting it. 
     */  
    if (mHolder.getSurface() == null){  
      // preview surface does not exist  
      return;  
    }  
    // stop preview before making changes  
    try {  
        mCamera.stopPreview();  
    } catch (Exception e){  
      // ignore: tried to stop a non-existent preview  
    }  
    try {  
        // Hard code camera surface rotation 90 degs to match Activity view in portrait  
        mCamera.setDisplayOrientation(90);  

        mCamera.setPreviewDisplay(mHolder);  
        mCamera.setPreviewCallback(previewCallback);  
        mCamera.startPreview();  
        mCamera.autoFocus(autoFocusCallback);  
    } catch (Exception e){  
        Log.d("DBG", "Error starting camera preview: " + e.getMessage());  
    }  
 }  
 }