本文实例为大家分享了Android绘图技巧使用的具体代码，供大家参考，具体内容如下

XML绘图

Bitmap

android:src="@drawable/giao"/>

Shape

android:shape="rectangle">

android:startColor="#FF5DA2FF"

android:endColor="#805FBBEF"

android:angle="45"/>

android:bottom="7dp"

android:top="7dp"

android:left="7dp"

android:right="7dp"/>

Layer(实现Photoshop中类似图层的概念)

android:left="10dip"

android:right="10dip"

android:top="10dip"

android:bottom="10dip"/>

android:left="200dp"

android:right="200dp"

android:top="200dp"

android:bottom="200dp"/>

Selector(帮助开发者实现静态绘图中的时间反馈)

android:right="10dp"

android:top="10dp"

android:bottom="10dp"/>

android:right="10dp"

android:top="10dp"

android:bottom="10dp"/>

Android绘图技巧

Canvas(作为绘制图形的直接对象)

Canvas.save();

可以理解为保存画布，作用是将之前的所有已经绘制图像保存起来，让后续的操作就好像在一个新的图层上操作一样

Canvas.restore();

可以理解为Photoshop中的合并图层操作，作用是将save()之后绘制的所有的图像与save()之前的图像进行合并

Canvas.translate();

坐标系的平移

Canvas.rotate();

坐标系的旋转

Layer图层

特别注意的是 saveLayerAlpha()与restore()要同时使用，才能够在canvas 画出多个层次，就是花多少层就要有多少对两个函数！

@Override

protected void onDraw(Canvas canvas) {

//super.onDraw(canvas);

drawLayer(canvas);

//图层同样是基于栈的结构进行管理的

@SuppressLint("DrawAllocation")

Paint paint=new Paint();

canvas.drawColor(Color.WHITE);

paint.setColor(Color.BLUE);

canvas.drawCircle(150,150,100,paint);

canvas.saveLayerAlpha(0,0,400,400,127);//入栈(创建新图层)

paint.setColor(Color.RED);

canvas.drawCircle(200,200,100,paint);

canvas.restore();//出栈

}

像素点分析

bitmap.getPixels(pixels,offset,stride,x,y,width,height);

参数含义如下：

pixels：接受位图颜色值的数组

offset：写入到pixels[]中的第一个索引值

stride：pixels[]的行间距

x:从位图中读取的第一个像素的x坐标值

y:从位图中读取的第一个像素的y坐标值

width:每一行中读取的像素宽度

height:读取的行数

画笔特效处理

PorterDuffXfermode

public class FilletView extends View {

private Bitmap bitmap,out;

private Paint paint;

public FilletView(Context context) {

super(context);

inView();

}

public FilletView(Context context, @Nullable AttributeSet attrs) {

super(context, attrs);

inView();

}

public FilletView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

inView();

}

private void inView(){

bitmap= BitmapFactory.decodeResource(getResources(), R.drawable.ask);

out=Bitmap.createBitmap(bitmap.getWidth(),bitmap.getHeight(),Bitmap.Config.ARGB_8888);

Canvas canvas=new Canvas(out);

paint=new Paint();

paint.setAntiAlias(true);

canvas.drawRoundRect(0,0,bitmap.getWidth(),bitmap.getHeight(),80,80,paint);

paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

canvas.drawBitmap(bitmap,0,0,paint);

}

@Override

protected void onDraw(Canvas canvas) {

canvas.drawBitmap(out,0,0,null);

}

}

Shader

BitmapShader：位图Shader

LinearGradient：线性Shader

RadialGradient：光束Shader

SweepGradient：梯度Shader

ComposeShader：混合Shader

private void useBitmapShader(Canvas canvas){

@SuppressLint("DrawAllocation")

Bitmap bitmap= BitmapFactory.decodeResource(getResources(), R.drawable.default_head);

@SuppressLint("DrawAllocation")

BitmapShader shader=new BitmapShader(bitmap, Shader.TileMode.REPEAT,Shader.TileMode.REPEAT);

@SuppressLint("DrawAllocation")

Paint paint=new Paint();

paint.setShader(shader);

canvas.drawCircle(500,200,200,paint);

}

Shader.TileMode.REPEAT：重复——横向、纵向不断重复

Shader.TileMode.CLAMP：拉伸——拉伸的图片最后的那个像素，不断重复

Shader.TileMode.MIRROR：镜像——横向不断翻转重复，横向不断翻转重复

PathEffect(各种笔触绘制一个路径)

CornerPathEffect：拐角处变得圆滑

DiscretePathEffect：线段上会产生许多杂点

DashPathEffect：绘制虚线

PathDashPathEffect：比DashPathEffect的功能更加强大，可以设置如方形点的虚线，圆形点的虚线。

ComposePathEffect：组合任意两种PathEffect路径组合形成新的效果

public class PathEffectView extends View {

private Paint paint;

private Path mainPath;

private PathEffect[] effects;

public PathEffectView(Context context, @Nullable AttributeSet attrs) {

super(context, attrs);

inView();

}

private void inView(){

paint=new Paint();

paint.setStyle(Paint.Style.STROKE);

paint.setStrokeWidth(5);

paint.setColor(Color.DKGRAY);

mainPath=new Path();

mainPath.moveTo(0,0);

for (int i = 0; i <= 30; i++) {

mainPath.lineTo(i*35, (float) (Math.random()*100));

}

effects=new PathEffect[6];

}

@SuppressLint("DrawAllocation")

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

effects[0]=null;

effects[1]=new CornerPathEffect(30);

effects[2]=new DiscretePathEffect(3,5);

effects[3]=new DashPathEffect(new float[]{20,10,5,10},0);

Path path=new Path();

path.addRect(0,0,8,8,Path.Direction.CCW);

effects[4]=new PathDashPathEffect(path,12,0,PathDashPathEffect.Style.ROTATE);

effects[5]=new ComposePathEffect(effects[3],effects[1]);

for (PathEffect effect : effects) {

paint.setPathEffect(effect);

canvas.drawPath(mainPath, paint);

canvas.translate(0, 200);

}

}

}

SurfaceView

SurfaceView与View的区别：

1、View主要适用于主动更新的情况下，而SurfaceView主要适用于被动更新，例如频繁的更新

2、View在主线程中对画面进行更新，而SurfaceView通常会通过一个子线程来进行页面的刷新

3、View在绘图时没有使用双缓冲机制，而SurfaceView在底层机制中就已经实现了双缓冲机制

总结：SurfaceView适合需要频繁刷新，或者刷新时数据处理量比较大

public class SurfaceViewTemplate extends SurfaceView implements SurfaceHolder.Callback ,Runnable{

//SurfaceHolder

private SurfaceHolder holder;

//用于绘画的Canvas

private Canvas canvas;

//子线程标志位

private boolean isDrawing;

private Paint paint;

private Path path;

private int x,y;

public SurfaceViewTemplate(Context context) {

super(context);

inView();

}

public SurfaceViewTemplate(Context context, AttributeSet attrs) {

super(context, attrs);

inView();

}

public SurfaceViewTemplate(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

inView();

}

private void inView(){

holder=getHolder();

holder.addCallback(this);

setFocusable(false);//焦点

setFocusableInTouchMode(true);

this.setKeepScreenOn(true);

path=new Path();

paint=new Paint(Paint.ANTI_ALIAS_FLAG);

paint.setColor(Color.RED);

paint.setStyle(Paint.Style.STROKE);

paint.setStrokeWidth(10);

paint.setStrokeCap(Paint.Cap.ROUND);

paint.setStrokeJoin(Paint.Join.ROUND);

}

@Override

public void surfaceCreated(@NonNull SurfaceHolder surfaceHolder) {

isDrawing=true;

path.moveTo(0,400);

new Thread(this).start();

}

@Override

public void surfaceChanged(@NonNull SurfaceHolder surfaceHolder, int i, int i1, int i2) {

}

@Override

public void surfaceDestroyed(@NonNull SurfaceHolder surfaceHolder) {

isDrawing=false;

}

@Override

public void run() {

while (isDrawing){

drawSome();

x+=1;

y= (int) (100*Math.sin(x*2*Math.PI/180)+400);

path.lineTo(x,y);

}

}

private void drawSome(){

try {

canvas=holder.lockCanvas();

//draw something...

canvas.drawColor(Color.WHITE);

canvas.drawPath(path,paint);

} catch (Exception e) {

e.printStackTrace();

} finally {

if (canvas!=null){

holder.unlockCanvasAndPost(canvas);

}

}

}

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。