values下面創attr

<resources>
    <attr name="mText" format="string" />
    <attr name="mTextColor" format="color" />
    <attr name="mTextSize" format="dimension" />
    <declare-styleable name="MyTextView">
        <attr name="mText"/>
        <attr name="mTextColor"
 
/>
        <attr name="mTextSize"/>
    </declare-styleable>
</resources>

獲取自定義屬性的值

package com.bwie.two;
import android.content.Context;
import android.content.Intent;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
 
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;
/**
 * 周旋
 * 2017/9/28  11:19
 */
public class MyView extends View{

    private String mText;
    private int mTextColor;
    private int mTextSize;
/**
     * 繪製時控制文字的控制範圍
     * @param context
*/
private Rect mBound
 
;
      private Paint mpaint;
    public MyView(Context context) {
        this(context,null);
}

    public MyView(Context context, AttributeSet attrs) {
        this(context, attrs,0);
}

    public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
//初始化
        //獲取自定義屬性的值
TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.MyTextView, defStyleAttr, 0);
mText = a.getString(R.styleable.MyTextView_mText);
mTextColor = a.getColor(R.styleable.MyTextView_mTextColor, Color.BLACK);
mTextSize = a.getDimensionPixelSize(R.styleable.MyTextView_mTextSize, 100);
a.recycle();  //注意回收
mpaint = new Paint();
mpaint.setTextSize(mTextSize);
mpaint.setColor(mTextColor);
//獲得繪製文字的寬和高
mBound = new Rect();
mpaint.getTextBounds(mText, 0, mText.length(), mBound);
}

    public MyView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
}

        @Override
protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
canvas.drawText(mText,getWidth()/2-mBound.width()/2,getHeight()/2+mBound.height()/2,mpaint);
}

}

xml 中使用

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
xmlns:openxu="http://schemas.android.com/apk/res-auto"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.bwie.two.MainActivity">
    <com.bwie.two.MyView
android:layout_width="200dip"
android:layout_height="100dip"
openxu:mTextSize="25sp"
openxu:mText="i love you"
openxu:mTextColor ="#0000ff"
android:background="#ff0000"/>
</RelativeLayout>