在 Android 4.0 及更高版本（API 级别 >= 14）上，您可以使用TextureView 预览摄像头流并使其不可见，以免向用户显示。方法如下：
首先创建一个类来实现一个 SurfaceTextureListener，它将获取预览表面的创建/更新回调。该类还接受一个相机对象作为输入，这样它就可以在表面创建后立即调用相机的 startPreview 函数：
public class CamPreview extends TextureView implements SurfaceTextureListener {
private Camera mCamera;
public CamPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
}
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
Camera.Size previewSize = mCamera.getParameters().getPreviewSize();
setLayoutParams(new FrameLayout.LayoutParams(
previewSize.width, previewSize.height, Gravity.CENTER));
try{
mCamera.setPreviewTexture(surface);
} catch (IOException t) {}
mCamera.startPreview();
this.setVisibility(INVISIBLE); // Make the surface invisible as soon as it is created
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
// Put code here to handle texture size change if you want to
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
return true;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surface) {
// Update your view here!
}
}
您还需要实现一个回调类来处理预览数据：
public class CamCallback implements Camera.PreviewCallback{
public void onPreviewFrame(byte[] data, Camera camera){
// Process the camera data here
}
}
使用上面的 CamPreview 和 CamCallback 类在您的活动的 onCreate() 或类似的启动函数中设置相机：
// Setup the camera and the preview object
Camera mCamera = Camera.open(0);
CamPreview camPreview = new CamPreview(Context,mCamera);
camPreview.setSurfaceTextureListener(camPreview);
// Connect the preview object to a FrameLayout in your UI
// You'll have to create a FrameLayout object in your UI to place this preview in
FrameLayout preview = (FrameLayout) findViewById(R.id.cameraView);
preview.addView(camPreview);
// Attach a callback for preview
CamCallback camCallback = new CamCallback();
mCamera.setPreviewCallback(camCallback);