Android：如何創建自定義相機預覽小部件？

我正在嘗試開發一個用於相機預覽的自定義小部件。我想用相機預覽填滿屏幕並在其上畫一些按鈕。Android：如何創建自定義相機預覽小部件？

我試圖創建一個自定義的widget的方式如下：

import java.io.IOException; 

import android.content.Context; 
import android.hardware.Camera; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 

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

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

}

和修改的main.xml文件的方式如下：

<RelativeLayout android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
xmlns:android="http://schemas.android.com/apk/res/android" 
android:id="@+id/RelativeLayout"> 
<dev.video.client.CapturePreview android:id="@+id/capturePreview" android:layout_width="wrap_content" android:layout_height="wrap_content"/> 
</RelativeLayout>

在Activity類我試圖綁定小部件的方式如下：

private CapturePreview mPreview; 

/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    setFullscreen(); 

    setContentView(R.layout.main); 

    this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); 

    //mPreview = new CapturePreview(this); 
    //setContentView(mPreview); 

    mPreview = (CapturePreview)this.findViewById(R.id.capturePreview); 
}

每次我嘗試調試應用程序時，我都會得到一條錯誤消息，我還沒有發現什麼可能是錯的。

我真的很感謝任何關於這個問題的幫助。

謝謝！

來源

2009-06-04 Niko Gamulin