Android UI

• 绘制
  • 自定义绘制主要是重写绘制方法，其中主要的方法就是onDraw()
  • 绘制的关键是Canvas的使用
    • Canvas的绘制类方法：drawxxx()(关键参数Paint)
    • Canvas辅助类方法：范围裁剪和几何变换
  • 可以使用不同的绘制方法来控制遮盖关系

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• • 自定义绘制的四个级别
    1. Canvas的drawxxx()方法及paint最常见的使用
    2. paint的完全攻略
       1. 拐角要什么形状
       2. 要不要开双线性过滤
       3. 加不加特效

1. 1. 3.canvas的范围裁剪
   2. 绘制顺序

   3. package com.safeluck.demo.demo.view;
      
      import android.content.Context;
      import android.graphics.Canvas;
      import android.graphics.Color;
      import android.graphics.Paint;
      import android.graphics.Path;
      import android.graphics.Rect;
      import android.graphics.RectF;
      import android.support.annotation.Nullable;
      import android.util.AttributeSet;
      import android.view.View;
      
      /**
       * Demo
       * Created by lzw on 2018/9/3. 15:09:45
       * 邮箱：632393724@qq.com
       * All Rights Saved! Chongqing AnYun Tech co. LTD
       */
      public class PractiseView1 extends View {
          Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
          private float interval = 25;
          private float perwidth = 80;
          public PractiseView1(Context context) {
              super(context);
          }
      
          public PractiseView1(Context context, @Nullable AttributeSet attrs) {
              super(context, attrs);
          }
      
          public PractiseView1(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
              super(context, attrs, defStyleAttr);
          }
      
          @Override
          protected void onDraw(Canvas canvas) {
              super.onDraw(canvas);
              RectF rectF1 = new RectF(100+1*interval+0*perwidth,600-5,100+perwidth*1+interval*1,600);
              RectF rectF2 = new RectF(100+2*interval+1*perwidth,600-30,100+perwidth*2+interval*2,600);
              RectF rectF3 = new RectF(100+3*interval+2*perwidth,600-30,100+perwidth*3+interval*3,600);
              RectF rectF4 = new RectF(100+4*interval+3*perwidth,600-200,100+perwidth*4+interval*4,600);
              RectF rectF5 = new RectF(100+5*interval+4*perwidth,600-50,100+perwidth*5+interval*5,600);
              RectF rectF6 = new RectF(100+6*interval+5*perwidth,600-90,100+perwidth*6+interval*6,600);
              RectF rectF7 = new RectF(100+7*interval+6*perwidth,600-160,100+perwidth*7+interval*7,600);
              paint.setColor(Color.GREEN);
              paint.setStyle(Paint.Style.FILL);
      
              canvas.drawRect(rectF1,paint);
              canvas.drawRect(rectF2,paint);
              canvas.drawRect(rectF3,paint);
              canvas.drawRect(rectF4,paint);
              canvas.drawRect(rectF5,paint);
              canvas.drawRect(rectF6,paint);
              canvas.drawRect(rectF7,paint);
      
              paint.setColor(Color.RED);
              canvas.drawLines(new float[]{100,20,100,600,100,600,1000,600},paint);
      
              paint.setTextSize(18);
              canvas.drawText("Froyo",100+1*interval+0.5f*perwidth,620,paint);
              canvas.drawText("GB",100+2*interval+1.5f*perwidth,620,paint);
              canvas.drawText("ICS",100+3*interval+2.5f*perwidth,620,paint);
              canvas.drawText("JB",100+4*interval+3.5f*perwidth,620,paint);
              canvas.drawText("KitKat",100+5*interval+4.5f*perwidth,620,paint);
              canvas.drawText("L",100+6*interval+5.5f*perwidth,620,paint);
              canvas.drawText("M",100+7*interval+6.5f*perwidth,620,paint);
      
              paint.setTextSize(24);
              paint.setColor(Color.BLACK);
              canvas.drawText("直方图",100+7*interval+3.5f*perwidth,680,paint);
          }
      }
      

      　　

      　　　

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