05Android学习从零单排之AndroidMultimedia（多媒体）

读了那么多年的书让我明白一个道理。人要稳重，不要想到啥就做啥。做一行越久即使你不会，几年之后慢慢的你也会了，加上一点努力你或许你能成为别人眼中的专家。

注：本章blog主要学习Android下图片、音频、视频的处理。

Android下大图片的处理

在平时开发中，如果我们加载一个图片分辨率或者加载批量图片，超过了手机的屏幕分辨率或者内存空间时，就会导致加载图片不成功，并会报OOM异常，所以为了解决这个问题，我们就需要通过一定比例的缩放，方便图片加载。

大图片缩放的步骤

1、获取当前手机屏幕的宽和高（分辨率）。
2、获取图片的宽和高。
3、用图片的分辨率除以当前屏幕的分辨率。
4、加载缩放后的图片资源。

protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ImageView imageView = (ImageView) findViewById(R.id.iv);// Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.dog);//执行到这里就是OOM了// imageView.setImageBitmap(bitmap);        //获取当前屏幕的宽高        WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);        Point point = new Point();        //TODO 注意测量屏幕的宽高和下面测量图片的宽高，这种写法，以前没遇到过。        /** * 基本顺序是 wm.getDefaultDisplay().getSize发现需要Point对象，就去new了 * 但是new完之后，Point不能直接使用，例如，不能直接point.x。 * 需要被wm装载到容器之后，才能执行point.x。不然获取不到屏幕的宽高。 */        wm.getDefaultDisplay().getSize(point);        int x = point.x;        int y = point.y;        Toast.makeText(this, "当前屏幕分辨率"+x+"*"+y, Toast.LENGTH_SHORT).show();        BitmapFactory.Options options = new BitmapFactory.Options();        //通过bitmap获取的资源图片的信息，而不是加载图片资源。        options.inJustDecodeBounds = true;        //Options        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dog,options);        //获取图片的宽高，方法同上        int outWidth = options.outWidth;        int outHeight = options.outHeight;        Toast.makeText(this, "获取到图片的分辨率："+outWidth+"*"+outHeight, Toast.LENGTH_SHORT).show();        //计算缩放比例        int scale = 1;        int scaleX = outWidth / x;        int scaleY = outHeight / y;        /** * scaleX>=scleY 是判断宽高比例 * scaleX>scale 是判断图片像素除以屏幕像素是否大于1，也就是不能比屏幕小才做缩放。 */        if (scaleX>=scaleY&&scaleX>scale) {            scale = scaleX;        }else if (scaleY >= scaleX && scaleY>scale) {            scale = scaleY;        }        //inSampleSize 可以把它看成setSampleSize,就是设置缩放后的图片大小。        options.inSampleSize = scale;        //开始真正加载图片资源了，不是获取图片信息了。        options.inJustDecodeBounds = false;        Bitmap bit = BitmapFactory.decodeResource(getResources(), R.drawable.dog,options);        int scaleWidth = options.outWidth;        int scaleHeight = options.outHeight;        Toast.makeText(this, "缩放后的图片分辨率："+scaleWidth+"*"+scaleHeight, Toast.LENGTH_SHORT).show();        imageView.setImageBitmap(bit);    }

Android对图片的修改操作

Android是不允许对图片的源文件进行直接修改的，必须要先复制改图片，才能对图片进行修改或涂鸦。

创建一个原图的副本（即复制图片）

@Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ButterKnife.bind(this);        btnRotate.setOnClickListener(this);        btnMove.setOnClickListener(this);        btnOverturn.setOnClickListener(this);        btnReflection.setOnClickListener(this);        resource = BitmapFactory.decodeResource(getResources(), R.drawable.meinv);        iv1.setImageBitmap(resource);        //给第二个ImageView设置和第一个一样的图片        bitmap = Bitmap.createBitmap(resource.getWidth()*2, resource.getHeight()*2, resource.getConfig());        //准备画布        canvas = new Canvas(bitmap);        //开始作画，参照第一张图片 Paint可以理解为笔        matrix = new Matrix();//        matrix.setRotate(30, bitmap.getWidth()/2, bitmap.getHeight()/2);        canvas.drawBitmap(resource, matrix, new Paint());        iv2.setImageBitmap(bitmap);    }

对创建的图片进行“旋转”、“移动”等操作。

1、旋转
matrix.setRotate(30);
2、平移
matrix.setTranslate(20, 0);
3、缩放
matrix.setScale(0.5f, 0.5f);
4、倒影
//对图片进行倒影效果
matrix.setScale(1.0f, -1.0f);
matrix.postTranslate(0, copyBitmap.getHeight());
5、翻转
//对图片进行镜面
matrix.setScale(-1.0f, 1.0f);
matrix.postTranslate(copyBitmap.getWidth(), 0);

public void onClick(View v) {        switch (v.getId()) {            case R.id.btn_rotate:                matrix.setRotate(30,bitmap.getWidth()/2,bitmap.getHeight()/2);                canvas.drawBitmap(resource, matrix, new Paint());                iv2.setImageBitmap(bitmap);                break;            case R.id.btn_move:                matrix.setTranslate(20,20);                canvas.drawBitmap(resource, matrix, new Paint());                iv2.setImageBitmap(bitmap);                break;            case R.id.btn_overturn:                //对图片进行镜面                matrix.setScale(-1.0f, 1.0f);                matrix.postTranslate(bitmap.getWidth(), 0);                canvas.drawBitmap(resource, matrix, new Paint());                iv2.setImageBitmap(bitmap);                break;            case R.id.btn_reflection:                //对图片进行倒影效果                matrix.setScale(1.0f, -1.0f);                matrix.postTranslate(0, bitmap.getHeight());                canvas.drawBitmap(resource, matrix, new Paint());                iv2.setImageBitmap(bitmap);                break;        }

Android版涂鸦板

通过Bitmap复制一张图片作为背景，然后获取到触摸事件，不断的在这张图上作画。
最后发送一条广播，通知图库更新。

protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        iv = (ImageView) findViewById(R.id.iv);        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bb);//        iv.setImageBitmap(bitmap);        //复制了一直带有属性的画板        newBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());        //准备画布        final Canvas canvas = new Canvas(newBitmap);        final Paint paint = new Paint();        canvas.drawBitmap(bitmap,new Matrix(),paint);        //在画布上画一条线//        canvas.drawLine(10,10,200,100,paint);        iv.setOnTouchListener(new View.OnTouchListener() {            int downX = 0;            int downY = 0;            @Override            public boolean onTouch(View v, MotionEvent event) {                switch (event.getAction()) {                    case MotionEvent.ACTION_DOWN:                        downX = (int) event.getX();                        downY = (int) event.getY();//                        Toast.makeText(MainActivity.this, "当前按下的坐标X:"+downX+"Y:"+downY, Toast.LENGTH_SHORT).show();                        break;                    case MotionEvent.ACTION_MOVE:                        int moveX = (int) event.getX();                        int moveY = (int) event.getY();                        paint.setStrokeWidth(3);//                        System.out.println("当前移动坐标X:" + moveX + "Y:" + moveY);                        canvas.drawLine(downX,downY,moveX,moveY,paint);                        iv.setImageBitmap(newBitmap);                        //重新计算坐标                        downX = (int) event.getX();                        downY = (int) event.getY();                        break;                    case MotionEvent.ACTION_UP:                        break;                }                return true;            }        });        iv.setImageBitmap(newBitmap);    }    public void saveImage(View view){        String path = Environment.getExternalStorageDirectory().getPath() + "/Download/" + "哈哈.png";//        String path = getFilesDir().getPath() + "/哈哈.png";        FileOutputStream fos = null;        try {            fos = new FileOutputStream(path);            boolean compress = newBitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);            if (compress) {                //发送一条广播，更新图库（已失效。）//                Intent intent = new Intent();//                intent.setAction(Intent.ACTION_MEDIA_MOUNTED);//                intent.setData(Uri.parse("file://"+getFilesDir()));//                sendBroadcast(intent);                //发送广播，通知图库更新（扫描文件）。                sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + Environment.getExternalStorageDirectory().getPath() + "/Download/")));                fos.close();                Toast.makeText(this, "涂鸦保存成功", Toast.LENGTH_SHORT).show();            }else {                Toast.makeText(this, "保存失败", Toast.LENGTH_SHORT).show();            }        } catch (Exception e) {            e.printStackTrace();        }    }

Android音频播放

相对来说Android下的音视频播放还是比较简单的，都被封装好在MediaPlay里面了，简单的Demo，几行代码就可以了。

public void startOpen(View view){        //初始化MediaPlay，根据官网copy一份，改下path就行了        MediaPlayer mediaPlayer = new MediaPlayer();        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);        try {            mediaPlayer.setDataSource("http://10.0.2.2/xpg.mp3");            mediaPlayer.prepare();            mediaPlayer.start();        } catch (IOException e) {            e.printStackTrace();        }    }

复杂点的，带服务后台播放加显示播放进度的Mp3播放器

混合方式开启音乐服务(就是为了调用服务里面的方法)

public class MainActivity extends AppCompatActivity {    private static final String TAG = "Hsia";    private Iservices iservices;    private static SeekBar mSB;    private MyConn myConn;    public static Handler handler = new Handler(){        @Override        public void handleMessage(Message msg) {            super.handleMessage(msg);            Bundle data = msg.getData();            //总大小            duration = data.getInt("duration");            //当前位置            currentPosition = data.getInt("currentPosition");            mSB.setMax(duration);            mSB.setProgress(currentPosition);        }    };    private static int currentPosition;    private static int duration;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Log.d(TAG, "onCreate: ");        mSB = ((SeekBar) findViewById(R.id.sb));// mSB.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {// //当SeekBar进度改变时// @Override// public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {// int position = seekBar.getProgress(); //获取当前播放的进度// //调用服务里面的方法更新更新到制定位置// iservices.callsetMusicProgress(position);// }//// @Override// public void onStartTrackingTouch(SeekBar seekBar) {//// }//// @Override// public void onStopTrackingTouch(SeekBar seekBar) {//// }// });        mSB.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {            //停止拖动回调            @Override            public void onStopTrackingTouch(SeekBar seekBar) {                int position = seekBar.getProgress();  //获取当前播放的进度                iservices.callsetMusicProgress(position);            }            //开始拖动            @Override            public void onStartTrackingTouch(SeekBar seekBar) {            }            //进度发生了改变            @Override            public void onProgressChanged(SeekBar seekBar, int progress,                                          boolean fromUser) {            }        });        Intent intent = new Intent(this,MusicServer.class);        startService(intent);        myConn = new MyConn();        bindService(intent, myConn,BIND_AUTO_CREATE);    }    class MyConn implements ServiceConnection{        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            Log.d(TAG, "onServiceConnected: ");            iservices = (Iservices)service;        }        @Override        public void onServiceDisconnected(ComponentName name) {        }    }    //开始    public void startMusic(View view) {        iservices.callStartMusic();    }    //暂停    public void stopMusic(View view) {        iservices.callStopMusic();    }    //重新播放    public void restartMusic(View view) {        iservices.callRestartMusic();    }    @Override    protected void onDestroy() {        super.onDestroy();        unbindService(myConn);    }}

在服务里面初始化MediaPlay（Iservices接口就不贴出来了）

public class MusicServer extends Service {    private static final String TAG = "Hsia";    private MediaPlayer mediaPlayer;    @Nullable    @Override    public IBinder onBind(Intent intent) {        return new MyBind();    }    @Override    public void onCreate() {        super.onCreate();        //初始化MediaPlay，根据官网copy一份，改下path就行了        mediaPlayer = new MediaPlayer();        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);        try {            mediaPlayer.setDataSource(Environment.getExternalStorageDirectory().getPath()+"/Download/"+"zxxpg.mp3");            mediaPlayer.prepareAsync();        } catch (IOException e) {            e.printStackTrace();        }    }    @Override    public void onDestroy() {        super.onDestroy();    }    private void startMusicService() {        mediaPlayer.start();        mediaPlayer.setLooping(false);        //更新进度条        updateSeekBar();    }    private void updateSeekBar() {        //获取音频的总文件长度        final int duration = mediaPlayer.getDuration();        //添加一个定时器，不断的更新SeekBar        Timer timer = new Timer();        TimerTask timerTask = new TimerTask() {            @Override            public void run() {                //获取当前播放进度                int currentPosition = mediaPlayer.getCurrentPosition();                //把数据发送出去                Message message = new Message();                Bundle bundle = new Bundle();                bundle.putInt("duration",duration);                bundle.putInt("currentPosition",currentPosition);                message.setData(bundle);                MainActivity.handler.sendMessage(message);            }        };        timer.schedule(timerTask,10,1000);    }    private void stopMusicService() {        mediaPlayer.pause();    }    private void restartMusicService() {        mediaPlayer.start();    }    private void setMusicProgress(int progress){        mediaPlayer.seekTo(progress);    }    //定义一个中间人对象，把想要暴露出去的方法暴露出去    class MyBind extends Binder implements Iservices {        @Override        public void callStartMusic() {            startMusicService();        }        @Override        public void callStopMusic() {            stopMusicService();        }        @Override        public void callRestartMusic() {            restartMusicService();        }        @Override        public void callsetMusicProgress(int progress) {            setMusicProgress(progress);        }    }}

Android视频播放

VideoView实现（封装好的简单几行代码）

VideoView mVideo = (VideoView) findViewById(R.id.vv);        mVideo.setVideoPath("http://10.0.2.2/vd.3gp");        //添加一个进度条        mVideo.setMediaController(new MediaController(this));        mVideo.start();

SurfaceView实现（VideoView是基于SurfaceView的封装）

SurfaceView mSV = (SurfaceView) findViewById(R.id.sv);        final SurfaceHolder holder = mSV.getHolder();        new Thread(new Runnable() {            @Override            public void run() {                try {                    Thread.sleep(100);                    final MediaPlayer mediaPlayer = new MediaPlayer();                    //设置播放数据源                    mediaPlayer.setDataSource("http://10.0.2.2/vd.mp4");                    //准备播放                    mediaPlayer.prepareAsync();                    mediaPlayer.setDisplay(holder);                    mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {                        @Override                        public void onPrepared(MediaPlayer mp) {                        mediaPlayer.start();                        }                    });                } catch (Exception e) {                    e.printStackTrace();                }            }        });

Android万能播放器

是通过使用vitamio第三方工程来实现的。官网
www.vitamio.org
- 1、导入vitamio库工程到AndroidStudio中。
AndroidStudio导入第三方库工程
- 2、vitamio基本用法和VideoView差不多。

Android拍照和摄像

打开照相机

 //打开照相机    public void openC(View view) {        //创建意图对象        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);        intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(Environment.getExternalStorageDirectory().getPath()+"/Download", "paizhao.png"))); // set the image file name        //开启意图 获取结果        startActivityForResult(intent, 0);    }

打开摄像机

//打开摄像机    public void openS(View view) {//创建意图对象        Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);        intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(Environment.getExternalStorageDirectory().getPath()+"/Download", "luxiang.3gp"))); // set the image file name        //开启意图 获取结果        startActivityForResult(intent, 0);    }

关于作者
- 个人网站：北京互联科技
- Email：[email protected]
- 项目地址:https://github.com/swordman20/Hsia05AndroidMultimedia.git

05Android学习从零单排之Androidmultimedia（多媒体）