android中的多媒体应用camera
MainActivity.java 代码 packagecom.amaker.ch11.app; importjava.io.File; importjava.io.FileOutputStream; importjava.io.IOException; importandroid.app.Activity; importandroid.graphics.PixelFormat; importandroid.hardware.Camera; importandroid.os.AsyncTask; importandroid.os.Bundle; importandroid.os.Environment; importandroid.view.KeyEvent; importandroid.view.SurfaceHolder; importandroid.view.SurfaceView; publicclassMainActivityextendsActivity{ //声明拍照界面组件SurfaceView privateSurfaceViewsurfaceView; //声明界面控制组件SurfaceHolder privateSurfaceHoldersurfaceHolder; //声明照相机 privateCameracamera; @Override publicvoidonCreate(BundlesavedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main); //实例化拍照界面组件 surfaceView=(SurfaceView)findViewById(R.id.preview); //从SurfaceView中获得SurfaceHolder surfaceHolder=surfaceView.getHolder(); //为SurfaceHolder添加回调 surfaceHolder.addCallback(surfaceCallback); surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } //响应按键事件 @Override publicbooleanonKeyDown(intkeyCode,KeyEventevent){ if(keyCode==KeyEvent.KEYCODE_CAMERA||keyCode==KeyEvent.KEYCODE_SEARCH){ takePic(); returntrue; } returnsuper.onKeyDown(keyCode,event); } //拍照方法 privatevoidtakePic(){ //停止预览 camera.stopPreview(); //拍照 camera.takePicture(null,null,pictureCallback); } //照片回调 Camera.PictureCallbackpictureCallback=newCamera.PictureCallback(){ @Override publicvoidonPictureTaken(byte[]data,Cameracamera){ newSavePictureTask().execute(data); camera.startPreview(); } }; //保存照片任务类 classSavePictureTaskextendsAsyncTask<byte[],String,String>{ @Override protectedStringdoInBackground(byte[]...params){ //创建文件 Filepicture=newFile(Environment.getExternalStorageDirectory(),"picture.jpg"); //如果文件存在删除掉 if(picture.exists())picture.delete(); try{ //获得文件输出流 FileOutputStreamfos=newFileOutputStream(picture.getPath()); //写到该文件 fos.write(params[0]); //关闭文件流 fos.close(); }catch(Exceptione){ e.printStackTrace(); } returnnull; } } //SurfaceHodler回调，处理打开相机，关闭相机以及照片尺寸的改变 SurfaceHolder.CallbacksurfaceCallback=newSurfaceHolder.Callback(){ @Override publicvoidsurfaceCreated(SurfaceHolderholder){ //打开相机 camera=Camera.open(); try{ //设置预览 camera.setPreviewDisplay(holder); }catch(IOExceptione){ e.printStackTrace(); } } @Override publicvoidsurfaceChanged(SurfaceHolderholder,intformat,intwidth, intheight){ //获得相机参数 Camera.Parametersparameters=camera.getParameters(); //设置照片大小 parameters.setPreviewSize(width,height); //设置照片格式 parameters.setPictureFormat(PixelFormat.JPEG); //设置相机参数 camera.setParameters(parameters); //开始预览 camera.startPreview(); } @Override publicvoidsurfaceDestroyed(SurfaceHolderholder){ //停止预览 camera.stopPreview(); //释放相机资源 camera.release(); camera=null; } }; } 代码 package com.amaker.ch11.app; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import android.app.Activity; import android.graphics.PixelFormat; import android.hardware.Camera; import android.os.AsyncTask; import android.os.Bundle; import android.os.Environment; import android.view.KeyEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; public class MainActivity extends Activity { // 声明拍照界面组件SurfaceView private SurfaceView surfaceView; // 声明界面控制组件SurfaceHolder private SurfaceHolder surfaceHolder; // 声明照相机 private Camera camera; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // 实例化拍照界面组件 surfaceView = (SurfaceView)findViewById(R.id.preview); // 从SurfaceView中获得SurfaceHolder surfaceHolder = surfaceView.getHolder(); // 为SurfaceHolder 添加回调 surfaceHolder.addCallback(surfaceCallback); surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } // 响应按键事件 @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if(keyCode==KeyEvent.KEYCODE_CAMERA||keyCode==KeyEvent.KEYCODE_SEARCH){ takePic(); return true; } return super.onKeyDown(keyCode, event); } // 拍照方法 private void takePic(){ // 停止预览 camera.stopPreview(); // 拍照 camera.takePicture(null,null, pictureCallback); } // 照片回调 Camera.PictureCallback pictureCallback = new Camera.PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { new SavePictureTask().execute(data); camera.startPreview(); } }; // 保存照片任务类 class SavePictureTask extends AsyncTask<byte[],String,String>{ @Override protected String doInBackground(byte[]... params) { // 创建文件 File picture = new File(Environment.getExternalStorageDirectory(),"picture.jpg"); // 如果文件存在删除掉 if(picture.exists())picture.delete(); try { // 获得文件输出流 FileOutputStream fos = new FileOutputStream(picture.getPath()); // 写到该文件 fos.write(params[0]); // 关闭文件流 fos.close(); } catch (Exception e) { e.printStackTrace(); } return null; } } // SurfaceHodler 回调，处理打开相机，关闭相机以及照片尺寸的改变 SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() { @Override public void surfaceCreated(SurfaceHolder holder) { // 打开相机 camera = Camera.open(); try { // 设置预览 camera.setPreviewDisplay(holder); } catch (IOException e) { e.printStackTrace(); } } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { // 获得相机参数 Camera.Parameters parameters = camera.getParameters(); // 设置照片大小 parameters.setPreviewSize(width, height); // 设置照片格式 parameters.setPictureFormat(PixelFormat.JPEG); // 设置相机参数 camera.setParameters(parameters); // 开始预览 camera.startPreview(); } @Override public void surfaceDestroyed(SurfaceHolder holder) { // 停止预览 camera.stopPreview(); // 释放相机资源 camera.release(); camera = null; } }; } 本文转自linzheng 51CTO博客，原文链接:http://blog.51cto.com/linzheng/1079348
