Android学习笔记_26_多媒体之拍照

一、配置文件：

　　需要引入摄像头权限，sdcard读写权限。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.takepicture"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >

        <!-- screenOrientation设置activity在屏幕上显示方式：横向 -->
        <activity
            android:name="com.example.takepicture.MainActivity"
            android:label="@string/app_name"
            android:screenOrientation="landscape" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
    <!-- 摄像头权限  -->
    <uses-permission android:name="android.permission.CAMERA" />
    <!-- 在SDCard中创建与删除文件权限 -->
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
    <!-- 往SDCard写入数据权限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

</manifest>

　　布局文件，当activity启动时在屏幕上横向显示，手指触摸屏幕时，出现拍照和对焦两个按钮，采用相对布局。

<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <SurfaceView
        android:id="@+id/surfaceView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <RelativeLayout
        android:id="@+id/buttonlayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone" >

        <Button
            android:id="@+id/autofouce"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_alignParentRight="true"
            android:layout_alignTop="@+id/takePicture"
            android:layout_marginRight="5dp"
            android:layout_toLeftOf="@+id/takePicture"
            android:onClick="takePicture"
            android:text="@string/autofouce" />

        <Button
            android:id="@+id/takePicture"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_alignParentRight="true"
            android:layout_marginRight="59dp"
            android:onClick="takePicture"
            android:text="@string/takepicture" />
    </RelativeLayout>

</RelativeLayout>

二、代码实现：

package com.example.takepicture;

import java.io.File;
import java.io.FileOutputStream;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;

public class MainActivity extends Activity {

    private View layout;
    private static final String TAG = "TakePicture";
    private SurfaceView surfaceView;
    private Camera camera;
    private boolean preview;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //设置窗口没有标题
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        //全屏显示
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        
        //getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);//高亮
        
        setContentView(R.layout.activity_main);
        layout= this.findViewById(R.id.buttonlayout);
        //确定surfaceView什么时候被时间
        surfaceView = (SurfaceView) this.findViewById(R.id.surfaceView);
        surfaceView.getHolder().addCallback(new SufaceListener());
        /*下面设置Surface不维护自己的缓冲区，而是等待屏幕的渲染引擎将内容推送到用户面前*/
        surfaceView.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        surfaceView.getHolder().setFixedSize(176, 144);    //设置分辨率
        surfaceView.getHolder().setKeepScreenOn(true);//设置高亮
    }
    
    //触摸事件
    public boolean onTouchEvent(MotionEvent event) {
        //手指按下屏幕
        if(event.getAction()==MotionEvent.ACTION_DOWN){
            layout.setVisibility(ViewGroup.VISIBLE);//显示布局
            return true;
        }
        return super.onTouchEvent(event);
    }

    private final class SufaceListener implements SurfaceHolder.Callback{
        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        }
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                Log.i(TAG, "surfaceCreated .... ");
                camera = Camera.open();//打开摄像头
                Camera.Parameters parameters = camera.getParameters();
                Log.i(TAG, parameters.flatten());//打印参数
                //WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
                //Display display = wm.getDefaultDisplay();
                //图片大小的设置要符合手机上图片大小，否则会出现参数设置错误
                //parameters.setPreviewSize(display.getWidth(), display.getHeight());//设置预览照片的大小
                parameters.setPreviewFrameRate(3);//每秒3帧
                parameters.setPictureFormat(PixelFormat.JPEG);//设置照片的输出格式
                parameters.set("jpeg-quality", 85);//照片质量
                //parameters.setPictureSize(display.getWidth(), display.getHeight());//设置照片的大小
                camera.setParameters(parameters);
                camera.setPreviewDisplay(surfaceView.getHolder());//通过SurfaceView显示取景画面
                camera.startPreview();
                preview = true;
                Log.i(TAG, "surfaceCreated .. end .. ");
            } catch (Exception e) {
                Log.e(TAG, e.toString());
            }
        }
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            //是否摄像头
            if(camera!=null){
                if(preview) camera.stopPreview();
                camera.release();
                camera = null;
            }
        }        
    }
    
    public void takePicture(View v){
        if (camera!=null) {
            switch (v.getId()) {
            case R.id.takePicture:
                Log.i(TAG, " start take picture ... ");
                //内部采用异步操作照片
                camera.takePicture(null, null, new PictureCallbackListener());
                Log.i(TAG, " end take picture ... ");
                break;
            case R.id.autofouce:
                camera.autoFocus(null);//自动对焦
                break;
            }
        }
    }
    /*
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if(camera!=null && event.getRepeatCount()==0){
            switch (keyCode) {
            case KeyEvent.KEYCODE_SEARCH:
                camera.autoFocus(null);//自动对焦
                break;
            case KeyEvent.KEYCODE_DPAD_CENTER:            
            case KeyEvent.KEYCODE_CAMERA:
                //拍照
                //camera.takePicture(null, null, new PictureCallbackListener());
                break;
            }
        }
        return true;
    }
*/
    private final class PictureCallbackListener implements Camera.PictureCallback{
        /**
         * data:所拍摄图片数据
         */
        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            try {
                Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
//                File file = new File(Environment.getExternalStorageDirectory(), "my.jpg");
                File file=new File("/storage/sdcard0/360/",System.currentTimeMillis()+".jpg");
                FileOutputStream outStream = new FileOutputStream(file);
                bitmap.compress(CompressFormat.JPEG, 100, outStream);
                outStream.close();
                //重新浏览，否则画面就不动
                   camera.stopPreview();
                camera.startPreview();
                preview = true;
            } catch (Exception e) {
                Log.e(TAG, e.toString());
            }
        }        
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

三、出现异常：

　　设置摄像头参数时，尤其是图片大小要符合手机匹配图片大小，否则会出现设置参数错误。