import android.app.Activity; import android.os.Bundle; import android.view.View; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; 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 GraphicesActivity 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); } } }