android学习之绘图总结

以下是程序的运行结果:

android学习之绘图总结_第1张图片

代码如下:

package com.example.njupt.zhb.canvastest;
import android.R.integer;
import android.app.Activity;    
import android.os.Bundle;    
import android.view.View;    
import android.content.Context;    
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;    
import android.graphics.Color;    
import android.graphics.DashPathEffect;
import android.graphics.Paint;    
import android.graphics.PathEffect;
import android.graphics.RectF;    
import android.graphics.Path;    
import android.graphics.Shader;    
import android.graphics.LinearGradient;  
//主程序中继承自Android.view.View的 MyView类,重写 MyView的onDraw()方法,   
//一开始就会运行绘制的工作,在onDraw()中以Paint将几何图形绘制在Canvas上,   
//以 paint.setColor() 改变图形颜色、以 paint.setStyle()的设置来控制画出的的   
//图形是空心还是实心。程序的最后一段,就是直接在Canvas写上文字,随着Paint对   
//象里的属性设置,也会有不同的外观模式。

public class MyDrawActivity extends Activity {    
    /** Called when the activity is first created. */   
    @Override   
    public void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);    
        /*设置ContentView为自定义的MyVieW*/   
        MyView myView=new MyView(this);    
        setContentView(myView); 
        
    }    
         
    /* 自定义继承View 的MyView*/   
    private class MyView extends View {    
         public MyView(Context context){    
            super(context) ;    
         }    
         
         /*重写onDraw()*/   
         @Override   
         protected void onDraw(Canvas canvas)    
         {       
              super.onDraw(canvas);    
              /*设置背景为白色*/   
              canvas.drawColor(Color.WHITE);    
                   
              Paint paint=new Paint();    
              /*去锯齿*/   
              paint.setAntiAlias(true);    
              /*设置paint的颜色*/   
              paint.setColor(Color.RED);    
              /*设置paint的 style 为STROKE:空心*/   
              paint.setStyle(Paint.Style.STROKE);    
              /*设置paint的外框宽度*/   
              paint.setStrokeWidth(3);    
                   
              /*画一个空心圆形*/   
              canvas.drawCircle(40, 40, 30, paint);    
              /*画一个空心正方形*/   
              canvas.drawRect(10, 90, 70, 150, paint);    
              /*画一个空心长方形*/   
              canvas.drawRect(10, 170, 70,200, paint);    
              /*画一个空心椭圆形*/   
              canvas.drawOval(new RectF(10,220,70,250), paint);    
              /*画一个空心三角形*/   
              Path path=new Path();    
              path.moveTo(10, 330);    
              path.lineTo(70,330);    
              path.lineTo(40,270);    
              path.close();    
              canvas.drawPath(path, paint);    
              /*画一个空心梯形*/   
              Path path1=new Path();    
              path1.moveTo(10, 410);    
              path1.lineTo(70,410);    
              path1.lineTo(55,350);    
              path1.lineTo(25, 350);    
              path1.close();    
              canvas.drawPath(path1, paint);    
                   
              /*设置paint的颜色*/   
              paint.setColor(Color.BLUE);    
              /*设置paint 的style为 FILL:实心*/   
              paint.setStyle(Paint.Style.FILL);    
              /*画一个实心圆*/   
              canvas.drawCircle(120,40,30, paint);    
              /*画一个实心正方形*/   
              canvas.drawRect(90, 90, 150, 150, paint);    
              /*画一个实心长方形*/   
              canvas.drawRect(90, 170, 150,200, paint);    
              /*画一个实心椭圆*/   
              RectF re2=new RectF(90,220,150,250);    
              canvas.drawOval(re2, paint);    
              /*画一个实心三角形*/   
              Path path2=new Path();    
              path2.moveTo(90, 330);    
              path2.lineTo(150,330);    
              path2.lineTo(120,270);    
              path2.close();    
              canvas.drawPath(path2, paint);    
              /*画一个实心梯形*/   
              Path path3=new Path();    
              path3.moveTo(90, 410);    
              path3.lineTo(150,410);    
              path3.lineTo(135,350);    
              path3.lineTo(105, 350);    
              path3.close();    
              canvas.drawPath(path3, paint);    
                   
              /*设置渐变色*/   
              Shader mShader=new LinearGradient(0,0,100,100,    
                      new int[]{Color.RED,Color.GREEN,Color.BLUE,Color.YELLOW},    
                      null,Shader.TileMode.REPEAT);    
              //Shader.TileMode三种模式    
              //REPEAT:沿着渐变方向循环重复    
              //CLAMP:如果在预先定义的范围外画的话,就重复边界的颜色    
              //MIRROR:与REPEAT一样都是循环重复,但这个会对称重复    
              paint.setShader(mShader);//用Shader中定义定义的颜色来话    
                
              /*画一个渐变色圆*/   
              canvas.drawCircle(200,40,30, paint);    
              /*画一个渐变色正方形*/   
              canvas.drawRect(170, 90, 230, 150, paint);    
              /*画一个渐变色长方形*/   
              canvas.drawRect(170, 170, 230,200, paint);    
              /*画一个渐变色椭圆*/   
              RectF re3=new RectF(170,220,230,250);    
              canvas.drawOval(re3, paint);    
              /*画一个渐变色三角形*/   
              Path path4=new Path();    
              path4.moveTo(170,330);    
              path4.lineTo(230,330);    
              path4.lineTo(200,270);    
              path4.close();    
              canvas.drawPath(path4, paint);    
              /*画一个渐变色梯形*/   
              Path path5=new Path();    
              path5.moveTo(170, 410);    
              path5.lineTo(230,410);    
              path5.lineTo(215,350);    
              path5.lineTo(185, 350);    
              path5.close();    
              canvas.drawPath(path5, paint);    
              /*写字*/   
              paint.setTextSize(24);    
              canvas.drawText("圆形", 240, 50, paint);    
              canvas.drawText("正方形", 240, 120, paint);    
              canvas.drawText("长方形", 240, 190, paint);    
              canvas.drawText("椭圆形", 240, 250, paint);    
              canvas.drawText("三角形", 240, 320, paint);    
              canvas.drawText("梯形", 240, 390, paint); 
              /*虚线和虚线圆*/
              paint.setStyle(Paint.Style.STROKE);  
              paint.setColor(Color.BLUE);
              DashPathEffect effects = new DashPathEffect(new float[]{5,5,5,5},1);  
              paint.setPathEffect(effects);
              canvas.drawCircle(120, 460, 50, paint);
              canvas.drawLine(0, 400, 240, 400, paint);
              /*画位图*/
              Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.lenna);
              RectF dst=new RectF(10,500,bitmap.getWidth()/2+10,bitmap.getHeight()/2+500);
              canvas.drawBitmap(bitmap, null, dst, paint);
         }  
         
    }    
}  


 

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