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android-自定义view创建概述

2024-07-13 04:02:20   217人阅读

1.创建继承view的类

 1 public class myview extends View{ 2  3     public myview(Context context, AttributeSet attrs) {  //构造器 4         super(context, attrs); 5         // TODO Auto-generated constructor stub 6     } 7      8     protected void onDraw(Canvas canvas) 9     {10         super.onDraw(canvas);            11         canvas.drawColor(Color.BLACK);            //绘制黑色背景12         Paint paint=new Paint();                  //创建画笔13         paint.setColor(Color.RED);14         canvas.drawRect(10,10,110,110, paint);    //画矩形15         canvas.drawText("这是字符串", 10, 130, paint);//写字16         RectF rf1=new RectF(10,130,110,230);     //定义一个矩形17         canvas.drawArc(rf1, 0, 45, true, paint);//画弧，顺时针18         canvas.drawLine(150, 10, 250, 110, paint);//画线19         RectF rf2=new RectF(150,130,250,230);20         canvas.drawOval(rf2, paint);          //画圆21         22     }23 24 }

上述是一个例子。

2.要调用这个myview，需要在layout.xml上调用，如

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" />    <com.example.myview.myview        android:id="@+id/myview"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        /></RelativeLayout>

com.example.myview是myview这个类的所在包，xml调用时，记得前面要加上包。

 

这个是另一个自定义view的例子

 1 package com.example.myview; 2  3 import android.content.Context; 4 import android.graphics.Bitmap; 5 import android.graphics.BitmapFactory; 6 import android.graphics.Canvas; 7 import android.graphics.Color; 8 import android.graphics.Paint; 9 import android.util.AttributeSet;10 import android.view.View;11 12 public class myview_picture extends View{13     Bitmap mb;14     Paint paint;15 16     public myview_picture(Context context, AttributeSet attrs) {17         super(context, attrs);18         // TODO Auto-generated constructor stub19         this.initBitmap();              //初始化图片20     }21     22     public void initBitmap()23     {24         paint=new Paint();25         mb=BitmapFactory.decodeResource(getResources(), R.drawable.indexgundom);26     }27     @Override28     protected void onDraw(Canvas canvas)29     {30         super.onDraw(canvas);31         paint.setAntiAlias(true);               //打开抗锯齿32         paint.setColor(Color.WHITE);            //设置画笔颜色33         paint.setTextSize(15);                 //我猜是设置字体大小34         canvas.drawBitmap(mb, 10,10, paint);     //画图35         canvas.drawText("图片的宽度："+mb.getWidth(), 20, 220, paint); //写字36         canvas.drawText("图片的高度"+mb.getHeight(), 150, 220, paint);37     }38     39 40 }


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