Android自定義錄像（一）之錄像功能實現(附demo源碼)

引言

最近在做一個項目，是有關用手機攝像頭做圖像實時識別的。所以裡面需要自定義一個錄像功能。該demo實現了錄像和錄像後文件的保存查看，錄像會實時自動對焦（AutoFocus）。根據功能分兩篇講述。這第一篇講述錄像基本實現思路和需要注意的點。後面附有github的demo源碼下載鏈接。

思路

*Android實現錄像主要依靠MediaRecorder和SurfaceView這兩個類。另外，因為需要對攝像頭參數做一些設定，所以也需要Camera類。它們的作用分別是：MediaRecorder通過控制錄像音視頻源和輸出編碼等；surfaceview則是作為View的存在提供用戶界面，在surfaceview的不同生命周期實現不同的操作；camera類則用於對攝像頭參數做一些設定，再調用MediaRecorder的setCamera() 方法將camera對象帶入。

代碼

1.布局

<framelayout android:baselinealigned="false" android:layout_height="fill_parent" android:layout_width="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android">
    
    
        
            
        
        

            
            

            
        
    
</framelayout>  

2.布局截圖：

<喎?/kf/ware/vc/" target="_blank" class="keylink">vcD4NCjxoNCBpZD0="3核心代碼及注釋">3.核心代碼及注釋：

package com.alanjet.videorecordertest;

import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.media.CamcorderProfile;
import android.media.MediaRecorder;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageButton;
import android.widget.Toast;

import java.io.File;
import java.util.Calendar;

public class MainActivity extends Activity implements SurfaceHolder.Callback {
    private static final String TAG = "MainActivity";
    private SurfaceView mSurfaceview;
    private ImageButton mBtnStartStop;
    private ImageButton mBtnSet;
    private ImageButton mBtnShowFile;
    private boolean mStartedFlg = false;
    private MediaRecorder mRecorder;
    private SurfaceHolder mSurfaceHolder;
    private Camera myCamera;
    private Camera.Parameters myParameters;
    private Camera.AutoFocusCallback mAutoFocusCallback=null;
    private boolean isView = false;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //重寫AutoFocusCallback接口
        mAutoFocusCallback=new Camera.AutoFocusCallback() {
        @Override
        public void onAutoFocus(boolean success, Camera camera) {
            if(success){
                Log.i(TAG, "AutoFocus: success...");
            }else {
                Log.i(TAG, "AutoFocus: failure...");
            }
        }
    };

    initScreen();
    setContentView(R.layout.activity_main);
    mSurfaceview  = (SurfaceView)findViewById(R.id.capture_surfaceview);
    mBtnStartStop = (ImageButton) findViewById(R.id.ib_stop);
    mBtnSet= (ImageButton) findViewById(R.id.capture_imagebutton_setting);
    mBtnShowFile= (ImageButton) findViewById(R.id.capture_imagebutton_showfiles);
    mBtnShowFile.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent=new Intent(MainActivity.this,ShowVideoActivity.class);
            startActivity(intent);
            finish();
        }
    });
    mBtnSet.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(MainActivity.this,"相機設置待開發~",Toast.LENGTH_SHORT).show();
        }
    });

    SurfaceHolder holder = mSurfaceview.getHolder();// 取得holder

    holder.addCallback(this); // holder加入回調接口


    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

}

    /**
     * 獲取系統時間，保存文件以系統時間戳命名
     */
    public static String getDate(){
        Calendar ca = Calendar.getInstance();
        int year = ca.get(Calendar.YEAR);          
        int month = ca.get(Calendar.MONTH);         
        int day = ca.get(Calendar.DATE);            
        int minute = ca.get(Calendar.MINUTE);       
        int hour = ca.get(Calendar.HOUR);         
        int second = ca.get(Calendar.SECOND);     

        String date = "" + year + (month + 1 )+ day + hour + minute + second;
        Log.d(TAG, "date:" + date);

        return date;
    }

    /**
     * 獲取SD path
     */
    public String getSDPath(){
        File sdDir = null;
        boolean sdCardExist = Environment.getExternalStorageState()
                .equals(android.os.Environment.MEDIA_MOUNTED); // 判斷sd卡是否存在
        if (sdCardExist)
        {
            sdDir = Environment.getExternalStorageDirectory();// 獲取跟目錄
            return sdDir.toString();
        }

        return null;
    }

    //初始化屏幕設置
    public void initScreen(){
        requestWindowFeature(Window.FEATURE_NO_TITLE);// 去掉標題欄
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);// 設置全屏

        // 設置橫屏顯示
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

        // 選擇支持半透明模式,在有surfaceview的activity中使用。
        getWindow().setFormat(PixelFormat.TRANSLUCENT);
    }

    //初始化Camera設置
    public void initCamera()
    {
        if(myCamera == null && !isView)
        {
            myCamera = Camera.open();
            Log.i(TAG, "camera.open");
        }
        if(myCamera != null && !isView) {
            try {
                myParameters = myCamera.getParameters();
                myParameters.setPreviewSize(1920, 1080);
                myParameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
                myCamera.setParameters(myParameters);
                myCamera.setPreviewDisplay(mSurfaceHolder);
                myCamera.startPreview();
                isView = true;
            } catch (Exception e) {
                // TODO: handle exception
                e.printStackTrace();
                Toast.makeText(MainActivity.this, "初始化相機錯誤",
                        Toast.LENGTH_SHORT).show();
            }
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
                               int height) {
        // TODO Auto-generated method stub
        mSurfaceHolder = holder;
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        mSurfaceHolder = holder;
        initCamera();
        mBtnStartStop.setOnClickListener(new View.OnClickListener() {

            @TargetApi(Build.VERSION_CODES.LOLLIPOP)
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                if (!mStartedFlg) {
                    // Start
                    if (mRecorder == null) {
                        mRecorder = new MediaRecorder(); // Create MediaRecorder
                    }
                    try {
                        myCamera.unlock();
                        mRecorder.setCamera(myCamera);
                        // Set audio and video source and encoder
                        // 這兩項需要放在setOutputFormat之前
                        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
                        mRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
                        mRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_720P));
                        mRecorder.setPreviewDisplay(mSurfaceHolder.getSurface());

                        // Set output file path
                        String path = getSDPath();
                        if (path != null) {

                            File dir = new File(path + "/VideoRecorderTest");
                            if (!dir.exists()) {
                                dir.mkdir();
                            }
                            path = dir + "/" + getDate() + ".mp4";
                            mRecorder.setOutputFile(path);
                            Log.d(TAG, "bf mRecorder.prepare()");
                            mRecorder.prepare();
                            Log.d(TAG, "af mRecorder.prepare()");
                            Log.d(TAG, "bf mRecorder.start()");
                            mRecorder.start();   // Recording is now started
                            Log.d(TAG, "af mRecorder.start()");
                            mStartedFlg = true;
                            mBtnStartStop.setBackground(getDrawable(R.drawable.rec_stop));
                        }
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                } else {
                    // stop
                    if (mStartedFlg) {
                        try {
                            mRecorder.stop();
                            mRecorder.reset();
                            mBtnStartStop.setBackground(getDrawable(R.drawable.rec_start));
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                    mStartedFlg = false;
                }
            }

        });
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        // surfaceDestroyed的時候同時對象設置為null
        mSurfaceview = null;
        mSurfaceHolder = null;
        if (mRecorder != null) {
            mRecorder.release();
            mRecorder = null;
        }
    }

    @Override
    protected void onRestart() {
        super.onRestart();
    }

    @Override
    protected void onResume() {
        super.onResume();
    }

    @Override
    protected void onStart() {
        super.onStart();
    }
}

4.manifest權限配置：

5.注意點：

Surfaceview主要是通過 SurfaceHolder holder = mSurfaceview.getHolder(); 中的SurfaceHolder來做控制的，SurfaceHolder加入回調接口holder.addCallback(this) 來重寫接口中的三個生命周期方法：public void surfaceChanged(), public void surfaceCreated(), public void surfaceDestroyed().

實現自動對焦的關鍵在於重寫Camera.AutoFocusCallback() 接口。並且需要將camera的parameters設置對焦模式為 myParameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO)。

6.運行截圖：

7.demo源代碼下載鏈接:

https://github.com/alanjet/VideoRecorderTest.git

後言

還有一篇博客《Android自定義錄像（二）之錄像文件保存查看實現(附demo源碼)》將在近期推出！

在實踐中求真知，在技術中尋快樂。這是自己在做項目中的一點小積累，希望能幫到有需要的Android開發小伙伴。這也是自己第一次寫csdn博客。可能表達得並不是很到位，一些地方寫的也比較稚嫩，歡迎大家在評論中多指點多交流，在技術之路上不斷前進。