[移动开发]Android之基础复习2D图形一，kotlin版权

int width;

int height;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

// 设置全屏，也可以在xml中进行设置 。

requestWindowFeature(Window.FEATURE_NO_TITLE);

getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,

WindowManager.LayoutParams.FLAG_FULLSCREEN);

setContentView(R.layout.main);

img = (ImageView) findViewById(R.id.img);

// 得到屏幕的宽和高。

Display display = getWindowManager().getDefaultDisplay();

width = display.getWidth();

height = display.getHeight();

// 创建图片，用来绘制。

bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);

// 创建画布，并且设置图片用来进行绘制。一个画布可以看成是整个屏幕。

canvas = new Canvas();

canvas.setBitmap(bitmap);

// 设置画笔，的各种属性。

//可以利用typeface设置外部字体

paint = new Paint();

paint.setAntiAlias(true);

paint.setColor(Color.RED);

paint.setStrokeWidth(10);

paint.setStyle(Paint.Style.FILL);

// 利用画布直接将内容绘制到bitmap上面。

canvas.drawCircle(50, 50, 30, paint);

//设定字体和各种格式

Typeface typeface = Typeface.create(“test”, Typeface.BOLD_ITALIC);

paint.setTypeface(typeface);

paint.setTextSize(25);

canvas.drawText(“我是被画出来的!”, 100, 50, paint);

//画线

paint.setColor(Color.GREEN);

canvas.drawLine(0, 0, width, height/2, paint);

//画一条路径；Path.moveTo

Path path = new Path();

paint.setColor(Color.BLUE);

//移动动位置

path.moveTo(150, 150);

//画线条

path.lineTo(150, 200);

path.lineTo(200, 210);

path.lineTo(30, 30);

canvas.drawPath(path, paint);

//从哪里开始画一个弧形

path.reset();

path.addCircle(230, 230, 10, Direction.CCW);

canvas.drawPath(path, paint);

// 将画好的图片显示到屏幕上面。

img.setImageBitmap(bitmap);

// 清空笔刷；

paint.reset();

}

}

下面看看一下转换方法：

1）Bitmap 转化为 byte

ByteArrayOutputStream out = new ByteArrayOutputStream();

bitmap.compress(Bitmap.CompressFormat

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.PNG, 100, out);

byte[] array= out.toByteArray();

2）byte转化为bitmap

final ContentResolver contentResolver = context.getContentResolver();

final PackageManager manager = context.getPackageManager();

final Cursor c = contentResolver.query(uri, null, null, null, null);

final int icon3DIndex = c.getColumnIndexOrThrow(ColumnName);

byte[] data = c.getBlob(icon3DIndex);

Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);

3）bitmap 转换 drawable

Bitmap bitmap = new Bitmap(…); Drawable drawable = new BitmapDrawable(bitmap);

//Drawable drawable = new FastBitmapDrawable(bitmap);

4）Drawable to Bitmap