自定义控件1--自定义属性

自定义控件是进阶的必经之路,整理一下自定义控件的知识.分享给大家.

1.自定义view属性

在values下建立一个xml文件,最好以attrs什么的开头,好区分,我这里建立了一个attrs_myview.xml的文件.

<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="MyView">
<attr name="radios" format="integer"/>
<attr name="mycolor" format="color"/>
</declare-styleable>
</resources>

2,声明

a,通用方式:xmlns:app="http://schemas.android.com/apk/res-auto"

b,一般方式xmlns:custom="http://schemas.android.com/apk/res/我的包名" 

<?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"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.king.myapplication.MainActivity">

<com.example.king.myapplication.MyView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ff0000"
android:padding="20dp"
app:radios="200"
app:mycolor="#00aaff"
/>

</RelativeLayout>

3,使用

得到方式也有两种,不过基本上也是一个意思的.

方式一

TypedArray arry = context.obtainStyledAttributes(attrs, R.styleable.MyView);
radius = (int)arry.getInteger(R.styleable.MyView_radios, 0);
mColor = arry.getColor(R.styleable.MyView_mycolor, Color.GREEN);
arry.recycle();


方式二
TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.MyView, defStyleAttr, 0);
int n = a.getIndexCount();
for (int i = 0; i < n; i++)
{
int attr = a.getIndex(i);
switch (attr)
{
case R.styleable.MyView_radios:
radius = a.getInteger(attr,0);
break;
case R.styleable.MyView_mycolor:
// 默认颜色设置为黑色
mColor = a.getColor(attr, Color.BLACK);
break;

}

}
a.recycle();

3.重写onMeasure();

setMeasuredDimension方法设置当前view的宽高,

这里要注意的一点事但我们设置为wrapContext其实是不起作用的,需要自己来配置.我简单些一下来看看 @Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
setMeasuredDimension(radius * 2 + paddingLeft + paddingRight, radius * 2 + paddingtop + paddingBottom);
}

4.重写onDraw();

在onDraw方法中我们可以图形和文字.

这里值得注意的是我们需要先初始化一个画笔,画笔会初始化一些绘图的属性,比如颜色,字体大小等等

但是绘图方法要在canvas(画布)中来做

mpaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mTextpaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mpaint.setColor(mColor);
mTextpaint.setColor(Color.BLACK);
mTextpaint.setTextSize(50);
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int width = getWidth();
int height = getHeight();
canvas.drawCircle(radius + paddingLeft, radius + paddingtop, radius, mpaint);
canvas.drawText(mText, width / 2 - paddingLeft, height / 2 - paddingtop, mTextpaint);
}

5.看个整体demo代码

package com.example.king.myapplication;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;

import java.util.HashSet;
import java.util.Random;
import java.util.Set;

/**
* Created by king on 2016/3/21.
*/
public class MyView extends View{
private int radius = 300;
private Paint mpaint;
private int paddingLeft;
private int paddingtop;
private int paddingRight;
private int paddingBottom;
private Paint mTextpaint;
private int mColor;
private String mText="hehe";

public MyView(Context context) {
super(context);
init();
}

public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray arry = context.obtainStyledAttributes(attrs, R.styleable.MyView);
radius = (int)arry.getInteger(R.styleable.MyView_radios, 0);
mColor = arry.getColor(R.styleable.MyView_mycolor, Color.GREEN);
arry.recycle();
init();
}

public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
/**
* 获得我们所定义的自定义样式属性
*/
//方式一
TypedArray arry = context.obtainStyledAttributes(attrs, R.styleable.MyView);
radius = (int)arry.getInteger(R.styleable.MyView_radios, 0);
mColor = arry.getColor(R.styleable.MyView_mycolor, Color.GREEN);
arry.recycle();

//方式二
// TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.MyView, defStyleAttr, 0);
// int n = a.getIndexCount();
// for (int i = 0; i < n; i++)
// {
// int attr = a.getIndex(i);
// switch (attr)
// {
// case R.styleable.MyView_radios:
// radius = a.getInteger(attr,0);
// break;
// case R.styleable.MyView_mycolor:
// // 默认颜色设置为黑色
// mColor = a.getColor(attr, Color.BLACK);
// break;
//
// }
//
// }
// a.recycle();

init();

}

private void init() {
mpaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mTextpaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mpaint.setColor(mColor);
mTextpaint.setColor(Color.BLACK);
mTextpaint.setTextSize(50);
paddingLeft = getPaddingLeft();
paddingtop = getPaddingTop();
paddingRight = getPaddingRight();
paddingBottom = getPaddingBottom();
this.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mText = randomText();
postInvalidate();
}
});
}
private String randomText()
{
Random random = new Random();
Set<Integer> set = new HashSet<Integer>();
while (set.size() < 4)
{
int randomInt = random.nextInt(10);
set.add(randomInt);
}
StringBuffer sb = new StringBuffer();
for (Integer i : set)
{
sb.append("" + i);
}

return sb.toString();
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
setMeasuredDimension(radius * 2 + paddingLeft + paddingRight, radius * 2 + paddingtop + paddingBottom);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int width = getWidth();
int height = getHeight();
canvas.drawCircle(radius + paddingLeft, radius + paddingtop, radius, mpaint);
canvas.drawText(mText, width / 2 - paddingLeft, height / 2 - paddingtop, mTextpaint);
}

@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);

}
}