Android12

计算机图形的表示方法

位图

一个一个像素点

算法:

位图图形的大小=位图的宽度 * 位图的高度 * 每一个像素点占据字节数
位图的宽度 * 位图的高度 是分辨率

BMP的格式:

单色位图 1个bit byte = 1/8

16色位图 4个bit byte = 4/8

256色位图 8个bit byte = 8/8

24位位图 24个bit byte = 24/8

矢量图

根据比例

加载图片到内存

public void loadImage(View view){    //加载一个图片到内存 显示到imageview的控件上.    Bitmap bitmap = BitmapFactory.decodeFile("mnt/sdcard/big.jpg");    //32位的位图, argb     iv.setImageBitmap(bitmap);}--------------------------------------BitmapFactory.decodeStream(is);(最多用)BitmapFactory.decodeFile("mnt/sdcard/big.jpg");(次多用(getFiles(),getcache(),SDcard中范围))BitmapFactory.decodeResource(res, id);(相对少)

Android下面的位图默认是32位
ARGB : alpha red green blue 每一个是8位

图片需要加载内存的大小(1.6M在硬盘) = 宽度 * 高度 * (32/8)(内存中15.4M)

加载大图片到内存

//加载一个图片到内存 显示到imageview的控件上.Options opts = new Options();//创建一个选项条件opts.inSampleSize = 4;//设置采样率,宽高分别是原图的1/4,总像素个数就变成原图的1/16Bitmap bitmap = BitmapFactory.decodeFile("mnt/sdcard/big.jpg", opts);//32位的位图, argb iv.setImageBitmap(bitmap);

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//1.得到图片的宽高信息.ExifInterface exif = new ExifInterface("mnt/sdcard/big.jpg");int width = exif.getAttributeInt(ExifInterface.TAG_IMAGE_WIDTH, 0);int height = exif.getAttributeInt(ExifInterface.TAG_IMAGE_LENGTH, 0);System.out.println("widtH:"+width);System.out.println("height:"+height);//2.获取屏幕的宽高WindowManager  wm = (WindowManager) getSystemService(WINDOW_SERVICE);int screenWidth = wm.getDefaultDisplay().getWidth();int screenHeight = wm.getDefaultDisplay().getHeight();System.out.println("屏幕width:"+screenWidth);System.out.println("屏幕height:"+screenHeight);

图片的缩放

public void processImage(View view){    //得到原始位图的对象    Bitmap srcBitmap = BitmapFactory.decodeFile("/mnt/sdcard/tu1.jpg");    iv_src.setImageBitmap(srcBitmap);    //缩放后 显示一个缩放后的图片 在iv_dest    //用代码编辑图片,最好处理都是图片在内存中的拷贝,不去处理原图.    Bitmap copyedBitmap = Bitmap.createBitmap(srcBitmap.getWidth(), srcBitmap.getHeight(), srcBitmap.getConfig());    //临摹.创建一个画板    Canvas canvas = new Canvas(copyedBitmap);    //创建画笔    Paint paint = new Paint();    paint.setColor(Color.BLACK);    //作画    Matrix matrix = new Matrix();//按照1:1的比例作画    matrix.setScale(0.6f, 0.6f);    canvas.drawBitmap(srcBitmap, matrix, paint);    iv_dest.setImageBitmap(copyedBitmap);}

图片的平移旋转镜面和倒影效果

//平移Bitmap copyedBitmap = Bitmap.createBitmap(srcBitmap.getWidth(), srcBitmap.getHeight(), srcBitmap.getConfig());//临摹.创建一个画板Canvas canvas = new Canvas(copyedBitmap);//创建画笔Paint paint = new Paint();paint.setColor(Color.BLACK);//作画Matrix matrix = new Matrix();//按照1:1的比例作画matrix.setTranslate(100, 100);canvas.drawBitmap(srcBitmap, matrix, paint);iv_dest.setImageBitmap(copyedBitmap);

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//旋转Bitmap copyedBitmap = Bitmap.createBitmap(srcBitmap.getWidth(), srcBitmap.getHeight(), srcBitmap.getConfig());//临摹.创建一个画板Canvas canvas = new Canvas(copyedBitmap);//创建画笔Paint paint = new Paint();paint.setColor(Color.BLACK);//作画Matrix matrix = new Matrix();//按照1:1的比例作画matrix.setRotate(180, srcBitmap.getWidth()/2, srcBitmap.getHeight()/2);canvas.drawBitmap(srcBitmap, matrix, paint);iv_dest.setImageBitmap(copyedBitmap);

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//镜面Canvas canvas = new Canvas(copyedBitmap);//创建画笔Paint paint = new Paint();paint.setColor(Color.BLACK);//作画Matrix matrix = new Matrix();//按照1:1的比例作画matrix.setScale(-1, 1);matrix.postTranslate(srcBitmap.getWidth(), 0);canvas.drawBitmap(srcBitmap, matrix, paint);iv_dest.setImageBitmap(copyedBitmap);

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//倒影Bitmap copyedBitmap = Bitmap.createBitmap(srcBitmap.getWidth(), srcBitmap.getHeight(), srcBitmap.getConfig());//临摹.创建一个画板Canvas canvas = new Canvas(copyedBitmap);//创建画笔Paint paint = new Paint();paint.setColor(Color.BLACK);//作画Matrix matrix = new Matrix();//按照1:1的比例作画matrix.setScale(1, -1);matrix.postTranslate(0, srcBitmap.getHeight());canvas.drawBitmap(srcBitmap, matrix, paint);iv_dest.setImageBitmap(copyedBitmap);

随手涂鸦的ui

• view水平方向线性布局

• 拖动条SeekBar

• ImageView

  // 设置画笔的颜色paint.setColor(Color.BLACK);// 设置画笔的宽度paint.setStrokeWidth(5);

随手涂鸦的核心逻辑

触摸事件的操作:

iv.setOnTouchListener(new OnTouchListener() {    @Override    public boolean onTouch(View v, MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:// 按下            case MotionEvent.ACTION_MOVE:// 移动            case MotionEvent.ACTION_UP:// 离开        return true;        //false代表的是事件没有处理完毕,等待事件处理完毕, true代表事件已经处理完毕了.    }}

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System.out.println("摸到");startX = (int) event.getX();startY = (int) event.getY();System.out.println("移动");int newX = (int) event.getX();int newY = (int) event.getY();//画直线canvas.drawLine(startX, startY, newX, newY, paint);iv.setImageBitmap(alterBitmap);// 记得重新初始化手指在屏幕上的坐标startX = (int) event.getX();startY = (int) event.getY();

随手涂鸦的细节

File file = new File(Environment.getExternalStorageDirectory(),        SystemClock.currentThreadTimeMillis() + ".jpg");FileOutputStream stream = new FileOutputStream(file);------------------------------------------  //保存图片的API,格式,质量,输出流sdcard位置alterBitmap.compress(CompressFormat.JPEG, 100, stream);//欺骗系统,插入SDcard的广播Intent intent = new Intent();intent.setAction(Intent.ACTION_MEDIA_MOUNTED);intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));sendBroadcast(intent);<!-- 写入SDcard的权限 --><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

撕衣服

    public boolean onTouch(View v, MotionEvent event) {        switch (event.getAction()) {        case MotionEvent.ACTION_DOWN:            x = (int) event.getX();            y = (int) event.getY();            for(int i=-3;i<4;i++){                for(int j=-3;j<4;j++){                    if(Math.sqrt(i*i+j*j)<=3){                        try {                            alterBitmap.setPixel(x+i, y+j, Color.TRANSPARENT);                        } catch (Exception e) {                            e.printStackTrace();                        }                    }                }            }            iv_pre.setImageBitmap(alterBitmap);            break;        case MotionEvent.ACTION_MOVE:            x = (int) event.getX();            y = (int) event.getY();            for(int i=-3;i<4;i++){                for(int j=-3;j<4;j++){                    if(Math.sqrt(i*i+j*j)<=3){                        try {                            alterBitmap.setPixel(x+i, y+j, Color.TRANSPARENT);                        } catch (Exception e) {                            e.printStackTrace();                        }                    }                }            }            iv_pre.setImageBitmap(alterBitmap);            break;        case MotionEvent.ACTION_UP:            break;        }        return true;// 事件结束被消费掉了    }});

getX和getRawX区别

getX到控件的距离

getRawX到屏幕的距离

图片的颜色处理

protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    sb_red = (SeekBar) findViewById(R.id.sb_red);    iv = (ImageView) findViewById(R.id.iv);    sb_red.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {        @Override        public void onStopTrackingTouch(SeekBar seekBar) {            int progress = seekBar.getProgress();            float result = progress/50.0f;            System.out.println("变化的百分比为:"+result);            ColorMatrix cm = new ColorMatrix();            cm.set(new float[] {                1*result, 0, 0, 0, 0,                0, 1, 0, 0, 0,                0, 0, 1, 0, 0,                0, 0, 0, 1, 0            });            paint.setColorFilter(new ColorMatrixColorFilter(cm));            canvas.drawBitmap(srcBitmap, new Matrix(), paint);            iv.setImageBitmap(copyedBitmap);        }                  });

音乐播放器的状态图

mediaPlayer = new MediaPlayer();final ProgressDialog pd = new ProgressDialog(this);pd.setMessage("正在缓冲...");mediaPlayer.reset();//设置播放的文件mediaPlayer.setDataSource(et_path.getText().toString().trim());mediaPlayer.prepare();//同步的准备pd.show();mediaPlayer.setOnErrorListener(new OnErrorListener() {    @Override    public boolean onError(MediaPlayer mp, int what, int extra) {        Toast.makeText(MainActivity.this, "播放失败,错误代码:"+what, 0).show();        return false;    }});public void pause(View view) {    if(mediaPlayer!=null&&mediaPlayer.isPlaying()){        mediaPlayer.pause();        return;    }    if(mediaPlayer!=null){        mediaPlayer.start();    }}public void stop(View view) {    if(mediaPlayer!=null){        mediaPlayer.stop();        mediaPlayer.release();        mediaPlayer = null;    }}

异步播放网络上的音乐文件

mediaPlayer.prepareAsync();//异步的准备,开启子线程去准备mediaPlayer.setOnPreparedListener(new OnPreparedListener() {    @Override    public void onPrepared(MediaPlayer mp) {        pd.dismiss();        mediaPlayer.start();    }});

soundpool

打篮球的声音是用soundpool做的,不是mediaPlayer

protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    soundPool = new SoundPool(3, AudioManager.STREAM_MUSIC, 0);    soundID = soundPool.load(this, R.raw.shoot, 1);}public void click(View view){    soundPool.play(soundID, 1.0f, 1.0f, 0, 0, 1.0f);}

视频播放器

protected void onCreate(Bundle savedInstanceState) {     VideoView vv  vv = (VideoView) findViewById(R.id.vv);    vv.setVideoPath("/mnt/sdcard/oppo.3gp");    MediaController mc = new MediaController(this);    //设置控制器 控制的是那一个videoview    mc.setAnchorView(vv);    //设置videoview的控制器为mc    vv.setMediaController(mc);    vv.start();}

SurfaceView子线程更新ui

/** * 演示SurfaceView控件的使用 * SurfaceView 单位时间内完成界面的大量多次更新 * 双缓冲机制 : * A线程----更新ui -----后台计算---更新ui * B线程----后台计算----更新ui  ---后台计算 * 可以在子线程更新ui */

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<Button    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:onClick="click"    android:text="开启子线程更新ui" /><SurfaceView    android:id="@+id/sv"    android:layout_width="match_parent"    android:layout_height="match_parent" />

surfaceview生命周期的回调

sv = (SurfaceView) findViewById(R.id.sv);//注册一个surfaceview控制器的回调sv.getHolder().addCallback(new Callback() {    @Override    public void surfaceDestroyed(SurfaceHolder holder) {        System.out.println("surface被销毁了");        flag = false;    }    @Override    public void surfaceCreated(SurfaceHolder holder) {        System.out.println("surface创建了");        flag = true;        new Thread(){            public void run() {                for(int i = 0;i<100;i++){                    if(!flag){                        return ;                    }                //界面里面内容显示的控制器                    SurfaceHolder holder = sv.getHolder();                    Canvas  canvas = holder.lockCanvas();                    canvas.drawColor(Color.BLACK);                    int radius = 5+i;                    Paint paint = new Paint();                    paint.setColor(Color.RED);                    canvas.drawCircle(250, 250, radius, paint);                    holder.unlockCanvasAndPost(canvas);                    SystemClock.sleep(100);                }            };        }.start();    }    @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width,            int height) {        System.out.println("surface大小发生了变化");    }});

采用surfaceview播放视频

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

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@Overridepublic void surfaceCreated(SurfaceHolder holder) {    System.out.println("surface被创建");    try {        mediaPlayer = new MediaPlayer();        mediaPlayer.setDataSource("/mnt/sdcard/oppo.3gp");        mediaPlayer.prepare();    } catch (Exception e) {        e.printStackTrace();    }    //指定多媒体的内容实在holder里面显示    mediaPlayer.setDisplay(holder);    mediaPlayer.start();    mediaPlayer.seekTo(sp.getInt("position", 0));}@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {    System.out.println("surface被销毁");    if(mediaPlayer!=null){        int position = mediaPlayer.getCurrentPosition();        Editor editor  = sp.edit();        editor.putInt("position", position);        editor.commit();        mediaPlayer.stop();        mediaPlayer.release();    }}

照相机拍照

public void takePic(View view){    //开启手机的照相机应用拍照获取返回值     // create Intent to take a picture and return control to the calling application    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);    file = new File(Environment.getExternalStorageDirectory(),SystemClock.uptimeMillis()+".jpg"); // create a file to save the image    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file)); // set the image file name    // start the image capture Intent    startActivityForResult(intent, 0);}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {    if(file!=null&&file.exists()&&file.length()>0){        System.out.println(file.getAbsolutePath());        ImageView iv = (ImageView) findViewById(R.id.iv);        iv.setImageURI(Uri.fromFile(file));    }    super.onActivityResult(requestCode, resultCode, data);}

视频的录制

public void takePic(View view){    //开启手机的照相机应用拍照获取返回值     // create Intent to take a picture and return control to the calling application    Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);    file = new File(Environment.getExternalStorageDirectory(),SystemClock.uptimeMillis()+".3gp"); // create a file to save the image    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file)); // set the image file name    // start the image capture Intent    startActivityForResult(intent, 0);}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {    if(file!=null&&file.exists()&&file.length()>0){        System.out.println(file.getAbsolutePath());        VideoView vv= (VideoView) findViewById(R.id.vv);        vv.setVideoPath(file.getAbsolutePath());        MediaController mc = new MediaController(this);        mc.setAnchorView(vv);        vv.setMediaController(mc);        vv.start();    }    super.onActivityResult(requestCode, resultCode, data);}

传感器的使用

protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    sm = (SensorManager) getSystemService(SENSOR_SERVICE);    //得到光传感器    Sensor sensor = sm.getDefaultSensor(Sensor.TYPE_LIGHT);    listener = new MyListnener();    sm.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_NORMAL);}private class MyListnener implements SensorEventListener{    //当传感器数据变化的调用的方法    @Override    public void onSensorChanged(SensorEvent event) {        float light = event.values[0];        System.out.println("光线强度:"+light);    }    //当传感器精度发生变化的时候调用的方法    @Override    public void onAccuracyChanged(Sensor sensor, int accuracy) {    }}@Overrideprotected void onDestroy() {    sm.unregisterListener(listener);    listener = null;    super.onDestroy();}

指南针

protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    sm = (SensorManager) getSystemService(SENSOR_SERVICE);    //得到方向传感器    Sensor sensor = sm.getDefaultSensor(3);    listener = new MyListnener();    sm.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_NORMAL);}private class MyListnener implements SensorEventListener{    //当传感器数据变化的调用的方法    @Override    public void onSensorChanged(SensorEvent event) {        //values[0]: 地磁北极和手机y轴的夹角,  0=北, 90=东, 180=南, 270=西         int angle = (int) event.values[0];        if(angle>0&&angle<90){            System.out.println("东北");        }else if (angle>90&&angle<180){            System.out.println("东南");        }else if(angle>180&&angle<270){            System.out.println("西南");        }else if(angle>270&&angle<360){            System.out.println("西北");        }else if(angle==0){            System.out.println("北");        }else if(angle==90){            System.out.println("东");        }else if(angle==180){            System.out.println("南");        }else if(angle==270){            System.out.println("西");        }    }    //当传感器精度发生变化的时候调用的方法    @Override    public void onAccuracyChanged(Sensor sensor, int accuracy) {    }}@Overrideprotected void onDestroy() {    sm.unregisterListener(listener);    listener = null;    super.onDestroy();}