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

 

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

 

<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

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