android自定义控件(三) 自定义属性

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在xml里建立属性,然后java代码里用typedArray获得这些属性,得到属性后,利用属性做一些事.例:得到xml里的color,赋给paint.

1.在res/values/下新建attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="CustomView2">
        <attr name="textColor" format="color" />
        <attr name="textSize" format="dimension" />
    </declare-styleable>
</resources>
<!-- name="CustomView1"控件名称 得到TypedArray时用 -->
<!-- name="textColor" 对应test:textColor -->
<!-- format="color" 对应构造方法里a.getColor(R.styleable.CustomView2_textColor, 0xFFFFFFFF); -->

format详解可参照http://blog.csdn.net/ethan_xue/article/details/7315064
2.主要看构造函数

public class CustomView2 extends View {

    private Paint mPaint2;
    private String mText = "drawText";

    public CustomView2(Context context, AttributeSet attrs) {
        super(context, attrs);
        mPaint2 = new Paint();
        // TypedArray是存放资源的array,1.通过上下文得到这个数组,attrs是构造函数传进来的,对应attrs.xml
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CustomView2);
        // 获得xml里定义的属性,格式为 名称_属性名 后面是默认值
        int textColor = a.getColor(R.styleable.CustomView2_textColor, 0xFFFFFFFF);
        float textSize = a.getDimension(R.styleable.CustomView2_textSize, 35);
        mPaint2.setColor(textColor);
        mPaint2.setTextSize(textSize);
        // 为了保持以后使用该属性一致性,返回一个绑定资源结束的信号给资源
        a.recycle();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        mPaint2.setStyle(Style.FILL);
        canvas.drawText(mText, 10, 60, mPaint2);
    }

}

3.布局

<?xml version="1.0" encoding="utf-8"?>
<!-- xmlns:test="http://schemas.android.com/apk/res/ethan.customview1" 包名 -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:test="http://schemas.android.com/apk/res/ethan.customview1"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<ethan.customview1.CustomView2
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    test:textColor="#f00"
    test:textSize="20sp"
    />
</LinearLayout>

4.效果图

下载地址 http://download.csdn.net/detail/ethan_xue/4108832