Android繪圖機制(二)——自定義View繪制形,圓形,三角形,扇形,橢圓,曲線,文字和圖片的坐標講解

1、Android繪圖機制（二）自定義View繪制形, 圓形, 三角形, 扇形, 橢圓, 曲線,文字和圖片的坐標講解我們要想畫好一些炫酷的View，首先我們得知道怎么去畫一些基礎(chǔ)的圖案，比如矩形，圓形，三角形，多邊形等.新建一個項目然后我們創(chuàng)建一個listview,每個圖案一個Activity,這樣看起來是不是很順眼 <ListView android:id="+id/listview" android:layout_width="wrap_content" android:layout_height="wrap_content"

2、/>編寫ListViewprivate ListView listview;/item上的數(shù)據(jù)源 private String name = "矩形", "圓形", "三角形", "扇形", "橢圓", "曲線","文字和圖片"/listview的adapterprivate ArrayAdapter<String>adapter;private void initView() /實例化listview listview = (ListV

3、iew) findViewById(R.id.listview); /實例化數(shù)據(jù)源 adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, name); /listview設(shè)置adapter listview.setAdapter(adapter); /listview設(shè)置點擊事件 listview.setOnItemClickListener(new AdapterView.OnItemClickListener() Override public void onItemClick

4、(AdapterView<?> parent, View view, int position, long id) /判斷點擊了第幾個 if (id = 0) /矩形 startActivity(new Intent(MainActivity.this, RectActivity.class); else if (id = 1) /圓形 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) /橢圓 startActivity(new Intent(MainActivity.this, OvalActivity.class); else if (id = 5) /曲線 startActivity(new Intent(MainActivity.this, PathActivity.class); else if

6、(id = 6) /曲線 startActivity(new Intent(MainActivity.this, TvIvActivity.class); );效果是這樣的后續(xù)可以添加1.矩形RectActivity好的，上面寫ListView的代碼是不是很簡單？拿我們新建一個RectActivity去畫點了，首先我們要新建一個RectView繼承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 /無參 public RectView(Context context) super(context); /有參 public RectView(Context context, AttributeSet attrs) super(context, attrs); Overrid

8、e protected void onDraw(Canvas canvas) super.onDraw(canvas); / 創(chuàng)建畫筆 Paint p = new Paint(); /設(shè)置實心 p.setStyle(Paint.Style.FILL); / 設(shè)置紅色 p.setColor(Color.BLACK); / 設(shè)置畫筆的鋸齒效果 p.setAntiAlias(true); /繪制 canvas.drawRect(50, 100, 300, 300, p); 截圖1.圓形CircleActivity我們還是新建一個CircleActivity去畫點了，首先我們要新建一個CircleVi

9、ew繼承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;/* * 圓 * Created by LGL on 2016/1/7. */public class

10、CircleView extends View int width; int height; /無參 public CircleView(Context context) super(context); init(); /有參 public CircleView(Context context, AttributeSet attrs) super(context, attrs); init(); private void init() /獲取屏幕的寬高 /Android繪圖機制（一）自定義View的基礎(chǔ)屬性和方法里面有講 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); / 設(shè)置畫筆的鋸齒效果 p.setAntiAlias(true); canvas.

12、drawCircle(width / 2, height / 2, width / 2, p); 截圖3.三角形TrigonActivity我們還是新建一個TrigonActivity去畫點了，首先我們要新建一個trigonView繼承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 /無參 public TrigonView(Context context) super(context); /有參 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); /實例化路徑 Path path = new Path(); path.moveTo(80, 200);/ 此點為多邊形的起點 path.lineTo(120, 250); path.lineTo(80, 250); path.close(); / 使這些點構(gòu)成封閉的多邊形 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); / 創(chuàng)建畫筆 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.橢圓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;/* * 橢圓 * 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); / 創(chuàng)建畫筆 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); 橢圓的思路和扇形是一樣的，這里就不演示了截圖6.曲線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); / 創(chuàng)建畫筆 Paint p = new Paint(); p.setColor(Color.BLACK); p.reset(); /設(shè)置空心 p.setStyle(Paint.Style.STROKE); Path path = new Path(); path.moveTo(100, 320);/設(shè)置Path的起點 path.quadTo(150, 310, 170, 400); /設(shè)置路徑點和終點 canvas.drawPath(path, p); 截圖7.文字和圖片TvIvActivitypackage com.lgl.view.view;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Can