自定义View

package bwie.day02view;

import android.content.Context;
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.util.TypedValue;
import android.view.View;

/**
 * Created by Zhengaihua on 2016/11/1.
 */
public class CustomCircular extends View {
    private Paint paint;//画笔
    private int mColor;
    private float radius;
    private TypedArray typedArray;
    private String mText;
    private float mRadius;
    private float mTextSize;
    private Rect rect;
    private int widthMode;
    private int widthSize;

    public CustomCircular(Context context) {
        this(context, null);
    }

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

    public CustomCircular(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        typedArray = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomCircular, defStyleAttr, 0);
        radius = 40;
        mText = typedArray.getString(R.styleable.CustomCircular_ztext);//获得文本
        mColor = typedArray.getInt(R.styleable.CustomCircular_zcolor, Color.GREEN);//获得颜色
        /**
         * 单位的互换，
         其中，第一个参数是你想要得到的单位，第二个参数是你想得到的单位的数值，
         比如：我要得到一个20sp，
         那么我就用TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 25,getResources().getDisplayMetrics())，
         返回的就是25sp对应的px数值了。
         */
        int px = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 20, getResources().getDisplayMetrics());
        mRadius = typedArray.getDimension(R.styleable.CustomCircular_radius, px);//获取半径
        int px1 = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 20, getResources().getDisplayMetrics());
        mTextSize = typedArray.getDimension(R.styleable.CustomCircular_ztextSzie, px1);
        typedArray.recycle();//释放资源
        paint = new Paint();
        rect = new Rect();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        widthMode = MeasureSpec.getMode(widthMeasureSpec);
        widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int width = 0;
        int height = 0;
        if (widthMode == MeasureSpec.EXACTLY) {
            width = widthSize;
        } else {

            width = (int) (4 * radius);

        }
        if (heightMode == MeasureSpec.EXACTLY) {
            height = heightSize;
        } else {
            height = (int) (4 * radius);
        }
        setMeasuredDimension(width, height);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        int width = getWidth();
        int height = getHeight();
        //画一个大圆
        paint.setColor(Color.YELLOW);
        canvas.drawCircle(width / 2, height / 2, radius * 2, paint);
        //画一个小圆
        paint.setColor(Color.WHITE);
        canvas.drawCircle(width / 2, height / 2, radius, paint);
        //
        String str = "gao";
        paint.setTextSize(mTextSize);
        paint.getTextBounds(str, 0, str.length(), rect);
        /**
         * 处理字体大小
         */
        if (rect.width() > radius) {
            paint.setTextSize(20);
            paint.getTextBounds(str, 0, str.length(), rect);
        }
        paint.setColor(Color.BLACK);
        canvas.drawText(str, width / 2 - rect.width() / 2, height / 2 + rect.height() / 2, paint);
    }
}

 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    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="bwie.day02view.MainActivity">

    <bwie.day02view.CustomCircular
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:ztext="nihao"
        app:ztextSzie="20dp" />
</RelativeLayout>

 

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <attr name="ztext" format="string" />
    <attr name="ztextSzie" format="dimension" />
    <attr name="radius" format="dimension" />
    <attr name="zcolor" format="color" />
    <declare-styleable name="CustomCircular">
        <attr name="ztext" />
        <attr name="ztextSzie" />
        <attr name="radius" />
        <attr name="zcolor" />
    </declare-styleable>
</resources>