view 画出一个形状,并在里面添加内容+文本居中

activity_main

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:custom="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent">

<lianxi.jdt.Circle
android:layout_width="100dp"
android:layout_height="100dp" />

</RelativeLayout>

 Circle.java

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
<
4000
span style="color:#000080;font-weight:bold;">import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

/**
* Created by lenovo on 2017/11/01.
*/

public class Circle extends View{

private Paint paint = new Paint();
public Circle(Context context) {
super(context);
}

public Circle(Context context, AttributeSet attrs) {
super(context, attrs);
}

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

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//整体的颜色
//canvas.drawColor(Color.YELLOW);

paint.setColor(Color.YELLOW);
//正方形
canvas.drawRect(0,0,200,200,paint);
//圆形

//canvas.drawCircle(200/2,200/2,100,paint);

float textWidth = paint.measureText("123");
Rect rextText = new Rect();
//        rextText.height() 获取字符串的高度
paint.getTextBounds("123", 0, "123".length(), rextText);
int x = getWidth()/2-rextText.width()/2;
int y = getHeight()/2+rextText.height()/2;
paint.setTextSize(15);
paint.setColor(Color.BLACK);
canvas.drawText("123",x,y,paint);