android自定义控件(二) 入门,继承View

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ps: 可根据apidemo里LableView,list4,list6学习

文档在dev guide/Framework Topics/User Interface/Building Custom Components

自定义控件的步骤:

1 View的工作原理

2 编写View类

3 为View类增加属性

4 绘制屏幕

5 响应用户消息

6 自定义回调函数

不多说,主要是Canvas, Paint, Path

[java] view
plaincopy

public class CustomView1 extends View {

private Paint mPaint;

// private static final String mText = "drawText";

private String mText = "drawText";

public CustomView1(Context context, AttributeSet attrs) {

super(context, attrs);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

mPaint = new Paint();

mPaint.setColor(Color.BLUE);

// FILL填充, STROKE描边,FILL_AND_STROKE填充和描边

mPaint.setStyle(Style.FILL);

canvas.drawRect(new Rect(10, 10, 100, 100), mPaint);// 画一个矩形

mPaint.setColor(Color.GREEN);

mPaint.setTextSize(35.0f);

canvas.drawText(mText, 10, 60, mPaint);

}

}

布局

[java] view
plaincopy

<pre name="code" class="java"><?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

>

<ethan.customview1.CustomView1

android:layout_width="wrap_content"

android:layout_height="wrap_content"

/>

</LinearLayout></pre><pre name="code" class="java"></pre>

效果图



注意,此时,在控件下放一个textView的话,是显示不出来的(TextView放在控件上面可以显示),以后再解决

下载地址 http://download.csdn.net/detail/ethan_xue/4108820