近期。在改动Android4.4的原生相机Camera2，非常习惯的去寻找SurfaceView。结果任凭我使用grep还是ack。都无法搜索到SurfaceView，最后还是通过代码CameraActivity-->CameraModule-->PhotoUI-->R.layout.photo_module找到。原来是使用了TextureView。不是非常了解此控件，百度之。在官方API文档中找到此控件：
官方文档大概的意思是：
TextureView能够用来显示内容流。这样一个内容流比如能够视频或者OpenGL的场景。
内容流能够来自本应用程序以及其它进程。
Textureview必须在硬件加速开启的窗体中。
与SurfaceView相比，TextureView不会创建一个单独的窗体。这使得它能够像一般的View一样运行一些变换操作，比方移动、动画等等，比如,你能够通过调用myView.setAlpha(0.5f)将TextureView设置成半透明。
使用TextureView非常easy：你须要使用的就是SurfaceTexture，SurfaceTexture能够用于呈现内容。
以下是我写一个小样例来演示怎样渲染相机预览到TextureView，在官方文档样例的基础上略微修改了一下：
main.xml:
CameraPreview.java:
import java.io.IOException;import android.annotation.SuppressLint;import android.content.Context;import android.graphics.SurfaceTexture;import android.hardware.Camera;import android.view.TextureView;@SuppressLint("NewApi")public class CameraPreview extends TextureView implements TextureView.SurfaceTextureListener { private Camera mCamera; private TextureView mTextureView; public CameraPreview(Context context , Camera camera) { super(context); mCamera = camera; // TODO Auto-generated constructor stub } public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {// mCamera = Camera.open(); try { mCamera.setPreviewTexture(surface); mCamera.startPreview(); } catch (IOException ioe) { // Something bad happened } } public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) { // Ignored, Camera does all the work for us } public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) { mCamera.stopPreview(); mCamera.release(); return true; } public void onSurfaceTextureUpdated(SurfaceTexture surface) { // Invoked every time there's a new Camera preview frame }} CameraTest.java:
import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.Date;import android.annotation.SuppressLint;import android.app.Activity;import android.content.Intent;import android.hardware.Camera;import android.hardware.Camera.PictureCallback;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.FrameLayout;import android.widget.Toast;import com.example.mycamera.R.id;@SuppressLint("NewApi")public class CameraTest extends Activity { public static final int MEDIA_TYPE_IMAGE = 1; public static final int MEDIA_TYPE_VIDEO = 2; private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100; private static final int CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE = 200; private Camera mCamera; private CameraPreview mPreview; private static final String TAG = "ERROR"; private PictureCallback mPicture = new PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE); if (pictureFile == null) { Log.d(TAG, "Error creating media file, check storage permissions: " + "e.getMessage()"); return; } try { FileOutputStream fos = new FileOutputStream(pictureFile); fos.write(data); fos.close(); } catch (FileNotFoundException e) { Log.d(TAG, "File not found: " + e.getMessage()); } catch (IOException e) { Log.d(TAG, "Error accessing file: " + e.getMessage()); } } }; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.main); // 创建Camera实例 mCamera = getCameraInstance(); // 创建Preview view并将其设为activity中的内容 mPreview = new CameraPreview(this, mCamera); mPreview.setSurfaceTextureListener(mPreview); //设置浑浊 mPreview.setAlpha(0.5f); FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); // preview.setAlpha(0.0f); preview.addView(mPreview); // 在Capture按钮中增加listener Button captureButton = (Button) findViewById(id.button_capture); captureButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // 从摄像头获取图片 mCamera.takePicture(null, null, mPicture); } }); } /** 安全获取Camera对象实例的方法 */ public static Camera getCameraInstance() { Camera c = null; try { c = Camera.open(); // 试图获取Camera实例 } catch (Exception e) { // 摄像头不可用（正被占用或不存在） } return c; // 不可用则返回null } /** 为保存图片或视频创建File */ private static File getOutputMediaFile(int type) { // 安全起见，在使用前应该 // 用Environment.getExternalStorageState()检查SD卡是否已装入 File mediaStorageDir = new File( Environment .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "MyCameraApp"); // 假设期望图片在应用程序卸载后还存在、且能被其他应用程序共享， // 则此保存位置最合适 // 假设不存在的话，则创建存储文件夹 if (!mediaStorageDir.exists()) { if (!mediaStorageDir.mkdirs()) { Log.d("MyCameraApp", "failed to create directory"); return null; } Log.d("MyCameraApp", "failed to create directory"); } // 创建媒体文件名称 String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss") .format(new Date()); File mediaFile; if (type == MEDIA_TYPE_IMAGE) { mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_" + timeStamp + ".jpg"); } else if (type == MEDIA_TYPE_VIDEO) { mediaFile = new File(mediaStorageDir.getPath() + File.separator + "VID_" + timeStamp + ".mp4"); } else { return null; } return mediaFile; } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) { if (resultCode == RESULT_OK) { // 捕获的图像保存到Intent指定的fileUri Toast.makeText(this, "Image saved to:\n" + data.getData(), Toast.LENGTH_LONG).show(); } else if (resultCode == RESULT_CANCELED) { // 用户取消了图像捕获 } else { // 图像捕获失败，提示用户 } } if (requestCode == CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE) { if (resultCode == RESULT_OK) { // 捕获的视频保存到Intent指定的fileUri Toast.makeText(this, "Video saved to:\n" + data.getData(), Toast.LENGTH_LONG).show(); } else if (resultCode == RESULT_CANCELED) { // 用户取消了视频捕获 } else { // 视频捕获失败。提示用户 } } } @Override protected void onPause() { super.onPause(); releaseCamera(); // 在暂停事件中马上释放摄像头 } private void releaseCamera() { if (mCamera != null) { mCamera.release(); // 为其他应用释放摄像头 mCamera = null; } }}