Android绘图机制(二)——自定义View绘制形,圆形,三角形,扇形,椭圆,曲线,文字和图片的坐标讲解

1、Android绘图机制（二）自定义View绘制形, 圆形, 三角形, 扇形, 椭圆, 曲线,文字和图片的坐标讲解我们要想画好一些炫酷的View，首先我们得知道怎么去画一些基础的图案，比如矩形，圆形，三角形，多边形等.新建一个项目然后我们创建一个listview,每个图案一个Activity,这样看起来是不是很顺眼 <ListView android:id="+id/listview" android:layout_width="wrap_content" android:layout_height="wrap_content"

2、/>编写ListViewprivate ListView listview;/item上的数据源 private String name = "矩形", "圆形", "三角形", "扇形", "椭圆", "曲线","文字和图片"/listview的adapterprivate ArrayAdapter<String>adapter;private void initView() /实例化listview listview = (ListV

3、iew) findViewById(R.id.listview); /实例化数据源 adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, name); /listview设置adapter listview.setAdapter(adapter); /listview设置点击事件 listview.setOnItemClickListener(new AdapterView.OnItemClickListener() Override public void onItemClick

4、(AdapterView<?> parent, View view, int position, long id) /判断点击了第几个 if (id = 0) /矩形 startActivity(new Intent(MainActivity.this, RectActivity.class); else if (id = 1) /圆形 startActivity(new Intent(MainActivity.this, CircleActivity.class); else if (id = 2) /三角形 startActivity(new Intent(MainActivi

5、ty.this, TrigonActivity.class); else if (id = 3) /扇形 startActivity(new Intent(MainActivity.this, SectorActivity.class); else if (id = 4) /椭圆 startActivity(new Intent(MainActivity.this, OvalActivity.class); else if (id = 5) /曲线 startActivity(new Intent(MainActivity.this, PathActivity.class); else if

6、(id = 6) /曲线 startActivity(new Intent(MainActivity.this, TvIvActivity.class); );效果是这样的后续可以添加1.矩形RectActivity好的，上面写ListView的代码是不是很简单？拿我们新建一个RectActivity去画点了，首先我们要新建一个RectView继承Viewpackage com.lgl.view.view;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;imp

7、ort android.graphics.Paint;import android.util.AttributeSet;import android.view.View;/* * 矩形 * Created by LGL on 2016/1/7. */public class RectView extends View /无参 public RectView(Context context) super(context); /有参 public RectView(Context context, AttributeSet attrs) super(context, attrs); Overrid

8、e protected void onDraw(Canvas canvas) super.onDraw(canvas); / 创建画笔 Paint p = new Paint(); /设置实心 p.setStyle(Paint.Style.FILL); / 设置红色 p.setColor(Color.BLACK); / 设置画笔的锯齿效果 p.setAntiAlias(true); /绘制 canvas.drawRect(50, 100, 300, 300, p); 截图1.圆形CircleActivity我们还是新建一个CircleActivity去画点了，首先我们要新建一个CircleVi

9、ew继承Viewpackage com.lgl.view.view;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.View;import android.view.WindowManager;/* * 圆 * Created by LGL on 2016/1/7. */public class

10、CircleView extends View int width; int height; /无参 public CircleView(Context context) super(context); init(); /有参 public CircleView(Context context, AttributeSet attrs) super(context, attrs); init(); private void init() /获取屏幕的宽高 /Android绘图机制（一）自定义View的基础属性和方法里面有讲 WindowManager wm = (WindowManager) g

11、etContext() .getSystemService(Context.WINDOW_SERVICE); width = wm.getDefaultDisplay().getWidth(); height = wm.getDefaultDisplay().getHeight(); Override protected void onDraw(Canvas canvas) super.onDraw(canvas); Paint p = new Paint(); p.setColor(Color.BLACK); / 设置画笔的锯齿效果 p.setAntiAlias(true); canvas.

12、drawCircle(width / 2, height / 2, width / 2, p); 截图3.三角形TrigonActivity我们还是新建一个TrigonActivity去画点了，首先我们要新建一个trigonView继承Viewpackage com.lgl.view.view;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;i

13、mport android.util.AttributeSet;import android.view.View;/* * 三角形 * Created by LGL on 2016/1/7. */public class TrigonView extends View /无参 public TrigonView(Context context) super(context); /有参 public TrigonView(Context context, AttributeSet attrs) super(context, attrs); Override protected void onDr

14、aw(Canvas canvas) super.onDraw(canvas); Paint p = new Paint(); p.setColor(Color.BLACK); /实例化路径 Path path = new Path(); path.moveTo(80, 200);/ 此点为多边形的起点 path.lineTo(120, 250); path.lineTo(80, 250); path.close(); / 使这些点构成封闭的多边形 canvas.drawPath(path, p); 4.扇形SectorActivitypackage com.lgl.view.view;impo

15、rt android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.RectF;import android.util.AttributeSet;import android.view.View;/* * 扇形 * Created by LGL on 2016/1/8. */public class SectorView extends View public SectorView

16、(Context context) super(text); public SectorView(Context context, AttributeSet attrs) super(context, attrs); Override protected void onDraw(Canvas canvas) super.onDraw(canvas); / 创建画笔 Paint p = new Paint(); p.setColor(Color.BLACK); RectF rectF = new RectF(60, 100, 200, 240); canvas.drawArc(rectF, 20

17、0, 130, true, p); 5.椭圆OvalActivitypackage com.lgl.view.view;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.RectF;import android.util.AttributeSet;import android.view.View;/* * 椭圆 * Created by LGL on 20

18、16/1/8. */public class OvalView extends View public OvalView(Context context) super(context); public OvalView(Context context, AttributeSet attrs) super(context, attrs); Override protected void onDraw(Canvas canvas) super.onDraw(canvas); / 创建画笔 Paint p = new Paint(); p.setColor(Color.BLACK); RectF r

19、ectF = new RectF(60, 100, 200, 240); rectF.set(210,100,250,130); canvas.drawOval(rectF, p); 椭圆的思路和扇形是一样的，这里就不演示了截图6.曲线PathActivitypackage com.lgl.view.view;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphic

20、s.Path;import android.util.AttributeSet;import android.view.View;/* * Created by LGL on 2016/1/8. */public class PathView extends View public PathView(Context context) super(context); public PathView(Context context, AttributeSet attrs) super(context, attrs); Override protected void onDraw(Canvas ca

21、nvas) super.onDraw(canvas); / 创建画笔 Paint p = new Paint(); p.setColor(Color.BLACK); p.reset(); /设置空心 p.setStyle(Paint.Style.STROKE); Path path = new Path(); path.moveTo(100, 320);/设置Path的起点 path.quadTo(150, 310, 170, 400); /设置路径点和终点 canvas.drawPath(path, p); 截图7.文字和图片TvIvActivitypackage com.lgl.view.view;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Can