一,构造一个view 继承自TextureView 因为camera里面接收这种数据,同时要实现TextureView.SurfaceTextureListener ,如此在有texture的时候才能及时处理
二,Camera.setPreviewTexture(surface) 设定预览的数据来源
三,
- public void cameraHasOpened() {
-
- SurfaceTexture surface = textureView._getSurfaceTexture();
- CameraInterface.getInstance().doStartPreview(surface, previewRate);
在open完后有一个回调函数,在这里就传了这么一个值,surface,如此数据就有了,就是会从镜头取到数据然后传到预览中去
如此,进行渲染也就变得简单了,只要给surfacetexture传入一个渲染数据就行了
Google自Android4.0出了TextureView,为什么推出呢?就是为了弥补Surfaceview的不足,另外一方面也是为了平衡GlSurfaceView,当然这是本人揣度的。关于TextureView、Surfaceview、SurfaceTexture、GLSurfaceView的关系,待咱家推出GLSurfaceview预览Camera后再专门分析。本文主要介绍使用TextureView预览Camera。
其实关于如何用TextureView预览Camera,官网已经给出了demo,参见这里。另外,链接1 链接2也给出了完整的预览Camera的demo,但都是一堆东西染在一块。本文就利用前文 搭建的一个轻量级的Camera框架来快速替换掉Surfaceview。因为用Surfaceview预览的话传一个SurfaceHolder进去,用Textureview预览的话需要传进去一个SurfaceTexture。其他的Camera流程不变。
一、新建CameraTextureView类继承TextureView,并实现TextureView.SurfaceTextureListener接口。实现这个接口就像实现SurfaceHolder.Callback,最主要的目的是在SurfaceTexture准备好后能够知道,也即onSurfaceTextureAvailable这个函数。
CameraTextureView.java
- "font-family:Comic Sans MS;font-size:18px;">package org.yanzi.camera.preview;
-
- import org.yanzi.camera.CameraInterface;
-
- import android.content.Context;
- import android.graphics.PixelFormat;
- import android.graphics.SurfaceTexture;
- import android.util.AttributeSet;
- import android.util.Log;
- import android.view.SurfaceHolder;
- import android.view.SurfaceView;
- import android.view.TextureView;
-
- public class CameraTextureView extends TextureView implements TextureView.SurfaceTextureListener {
- private static final String TAG = "yanzi";
- Context mContext;
- SurfaceTexture mSurface;
- public CameraTextureView(Context context, AttributeSet attrs) {
- super(context, attrs);
-
- mContext = context;
- this.setSurfaceTextureListener(this);
- }
- @Override
- public void onSurfaceTextureAvailable(SurfaceTexture surface, int width,
- int height) {
-
- Log.i(TAG, "onSurfaceTextureAvailable...");
- mSurface = surface;
-
- }
- @Override
- public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
-
- Log.i(TAG, "onSurfaceTextureDestroyed...");
- CameraInterface.getInstance().doStopCamera();
- return true;
- }
- @Override
- public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width,
- int height) {
-
- Log.i(TAG, "onSurfaceTextureSizeChanged...");
- }
- @Override
- public void onSurfaceTextureUpdated(SurfaceTexture surface) {
-
- Log.i(TAG, "onSurfaceTextureUpdated...");
-
- }
-
-
-
-
- public SurfaceTexture _getSurfaceTexture(){
- return mSurface;
- }
- }
-
二、在布局文件里把它加上就行了,因为他的父类就是View,当成一般的View就行
- <span style="font-family:Comic Sans MS;font-size:18px;"><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
- xmlns:tools="http://schemas.android.com/tools"
- android:layout_width="match_parent"
- android:layout_height="match_parent"
- tools:context=".CameraActivity" >
- <FrameLayout
- android:layout_width="wrap_content"
- android:layout_height="wrap_content" >
- <org.yanzi.camera.preview.CameraTextureView
- android:id="@+id/camera_textureview"
- android:layout_width="0dip"
- android:layout_height="0dip" />
- FrameLayout>
- <ImageButton
- android:id="@+id/btn_shutter"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:background="@drawable/btn_shutter_background"
- android:layout_alignParentBottom="true"
- android:layout_centerHorizontal="true"
- android:layout_marginBottom="10dip"/>
- RelativeLayout>
- span>
三、在CameraInterface里,我封装了两个函数:
- "font-family:Comic Sans MS;font-size:18px;">
-
-
-
- public void doStartPreview(SurfaceHolder holder, float previewRate){
- Log.i(TAG, "doStartPreview...");
- if(isPreviewing){
- mCamera.stopPreview();
- return;
- }
- if(mCamera != null){
- try {
- mCamera.setPreviewDisplay(holder);
- } catch (IOException e) {
-
- e.printStackTrace();
- }
- initCamera(previewRate);
- }
-
-
- }
-
-
-
-
- public void doStartPreview(SurfaceTexture surface, float previewRate){
- Log.i(TAG, "doStartPreview...");
- if(isPreviewing){
- mCamera.stopPreview();
- return;
- }
- if(mCamera != null){
- try {
- mCamera.setPreviewTexture(surface);
- } catch (IOException e) {
-
- e.printStackTrace();
- }
- initCamera(previewRate);
- }
-
- }
分别对应Surfaceview和TextureView预览。可以看到就是传进来的参数不一样,initCamera()的东西都一样。
- "font-family:Comic Sans MS;font-size:18px;"> private void initCamera(float previewRate){
- if(mCamera != null){
-
- mParams = mCamera.getParameters();
- mParams.setPictureFormat(PixelFormat.JPEG);
-
-
-
- Size pictureSize = CamParaUtil.getInstance().getPropPictureSize(
- mParams.getSupportedPictureSizes(),previewRate, 800);
- mParams.setPictureSize(pictureSize.width, pictureSize.height);
- Size previewSize = CamParaUtil.getInstance().getPropPreviewSize(
- mParams.getSupportedPreviewSizes(), previewRate, 800);
- mParams.setPreviewSize(previewSize.width, previewSize.height);
-
- mCamera.setDisplayOrientation(90);
-
-
- List focusModes = mParams.getSupportedFocusModes();
- if(focusModes.contains("continuous-video")){
- mParams.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
- }
- mCamera.setParameters(mParams);
- mCamera.startPreview();
-
-
-
- isPreviewing = true;
- mPreviwRate = previewRate;
-
- mParams = mCamera.getParameters();
- Log.i(TAG, "最终设置:PreviewSize--With = " + mParams.getPreviewSize().width
- + "Height = " + mParams.getPreviewSize().height);
- Log.i(TAG, "最终设置:PictureSize--With = " + mParams.getPictureSize().width
- + "Height = " + mParams.getPictureSize().height);
- }
- }
四、在Activity里,依旧开一个线程去open Camera:
- "font-family:Comic Sans MS;font-size:18px;"> Thread openThread = new Thread(){
- @Override
- public void run() {
-
- CameraInterface.getInstance().doOpenCamera(CameraActivity.this);
- }
- };
- openThread.start();
在Camera Open完的回调里开预览:
- "font-family:Comic Sans MS;font-size:18px;"> @Override
- public void cameraHasOpened() {
-
- SurfaceTexture surface = textureView._getSurfaceTexture();
- CameraInterface.getInstance().doStartPreview(surface, previewRate);
- }
之后就能正常运行了,可以看到与前文Surfaceview预览Camera 改动非常之小。
几个注意事项:
1、TextureView是Android 4.0之后加入的,低版本么这个类。TextureView必须工作在开启硬件加速的环境中,也即配置文件里Activity的设置项里:android:hardwareAccelerated="true" 默认的这个属性就是true,因此不用再写了。但如果写成false,可以看到onSurfaceTextureAvailable()这个回调就进不来了,TextureView没有了SurfaceTexture还玩个屁啊。
2、本文demo打开camera并预览的正常log是:
- Line 417: 06-22 12:37:43.682 I/yanzi ( 4917): Camera open....
- Line 489: 06-22 12:37:43.758 I/yanzi ( 4917): onSurfaceTextureAvailable...
- Line 533: 06-22 12:37:43.819 I/yanzi ( 4917): Camera open over....
- Line 535: 06-22 12:37:43.819 I/yanzi ( 4917): doStartPreview...
- Line 537: 06-22 12:37:43.825 I/yanzi ( 4917): PictureSize : w = 1280h = 720
- Line 539: 06-22 12:37:43.825 I/yanzi ( 4917): PreviewSize:w = 800h = 448
- Line 555: 06-22 12:37:43.874 I/yanzi ( 4917): 最终设置:PreviewSize--With = 800Height = 448
- Line 557: 06-22 12:37:43.874 I/yanzi ( 4917): 最终设置:PictureSize--With = 1280Height = 720
- Line 577: 06-22 12:37:44.106 I/yanzi ( 4917): onSurfaceTextureUpdated...
- Line 579: 06-22 12:37:44.138 I/yanzi ( 4917): onSurfaceTextureUpdated...
- Line 583: 06-22 12:37:44.169 I/yanzi ( 4917): onSurfaceTextureUpdated...
- Line 585: 06-22 12:37:44.220 I/yanzi ( 4917): onSurfaceTextureUpdated...
- Line 587: 06-22 12:37:44.253 I/yanzi ( 4917): onSurfaceTextureUpdated...
测试手机为中兴Geek,这个手机Camera还是很牛逼的,比手里的华为G700强,就是偶尔会连不上Camera Service,汗。从log可以看到,onSurfaceTextureAvailable这个回调需要一定时间。Camera.open()这句话用了130多ms。但有两点跟Surfaceview不同。第一,TextureView创建过程中没有进到onSurfaceTextureSizeChanged()这个函数里。而SurfaceView在创建过程中,从无到有的时候会进到大小发生变化回调里。第二,onSurfaceTextureUpdated()这个函数每上来一帧数据,这块就进来一次。这是跟Surfaceview相比,最伟大的一个地方。通过这个接口,可以将上来的SurfaceTexture送给OpenGL再去处理。这个回调是实时的,而非用Camera的PreviewCallback这种2次回调的方式。从时间看,基本上每32ms左右上来一帧数据,即每秒30帧,跟本手机的Camera的性能吻合。
3、Camera再执行startPreview时必须保证TextureView的SurfaceTexture上来了,如果因为一些性能原因onSurfaceTextureAvailable()这个回调上不来就开预览,就开不了的。如果发生这种情况,就在onSurfaceTextureAvailable()回调里执行open和startPreview操作,保证万无一失。
4、TextureView本身就有getSurfaceTexture()这个函数,我又封装了个:
- "font-family:Comic Sans MS;font-size:18px;">
-
-
- public SurfaceTexture _getSurfaceTexture(){
- return mSurface;
- }
这里的mSurface就是onSurfaceTextureAvailable()回调里传上来的SurfaceTexture。测试证明,开预览时直接调
textureView.getSurfaceTexture(),把它传给Camera: mCamera.setPreviewTexture(surface);也是能正常预览的。但是推荐使用前者,原因见官方上的这段话:
A TextureView's SurfaceTexture can be obtained either by invoking getSurfaceTexture()
or by using a TextureView.SurfaceTextureListener
. It is important to know that a SurfaceTexture is available only after the TextureView is attached to a window (and onAttachedToWindow()
has been invoked.) It is therefore highly recommended you use a listener to be notified when the SurfaceTexture becomes available.
两种方式获得SurfaceTexture,推荐使用监听。因为只有在TextureView执行完onAttachedToWindow时,它的tSurfaceTexture才上来。
5、SurfaceTexture和TextureView的关系:
Using a TextureView is simple: all you need to do is get its SurfaceTexture
. The SurfaceTexture
can then be used to render content
如果说TextureView是一幅画的话,那SurfaceTexture就是画布,真正渲染的载体是SurfaceTexture。
6、TextureView可以像一般View执行各种变化,其中有个textureView.setAlpha(1.0f);默认不写这句话,它的alpha也是1.0f,即不透明。如果设成透明0.0f,可以看到啥都看不到了,这一点跟Surfaceview刚好相反。Surfaceview的SurfaceHolder一般要设一下Transparent即透明。但TextureView因为是个view,任何一个png的照片透明度设成0肯定啥都看不到。
7、如果认为预览个Camera这就是TextureView和SurfaceTexture的使命的话,就大错特错了,真正用意是和OpenGL无缝连接。
--------------------本文系原创,转载请注明作者yanzi1225627
版本号:PlayCamera_V2.0.0[2014-6-22].zip
CSDN下载链接:http://download.csdn.net/detail/yanzi1225627/7540903