自定义控件_day03

自定义控件的实战（参考网上的资料 比着葫芦画瓢）

自定义属性

在res/values下面新建attrs.xml属性文件<?xml version="1.0" encoding="utf-8"?><resources>    <!--name 是自定义属性名，一般采用驼峰命名，可以随意。 format 是属性的单位-->    <attr name="titleSize" format="dimension"></attr>    <attr name="titleText" format="string"></attr>    <attr name="titleColor" format="color"></attr>    <attr name="titleBackgroundColor" format="color"></attr>    <!--name 是自定义控件的类名-->    <declare-styleable name="MyCustomView">        <attr name="titleSize"></attr>        <attr name="titleText"></attr>        <attr name="titleColor"></attr>        <attr name="titleBackgroundColor"></attr>    </declare-styleable></resources>如上面的xml文件第一部分是公共的属性，第二部分是自定义控件MyCustomView的主题样式，该主题样式里的属性必须包含在公共属性里面。言外之意就是公共属性可以被多个自定义控件主题样式使用。

自定义控件的实现

package com.example.mytextview;import android.content.Context;import android.content.res.Resources;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.Log;import android.view.View;public class MyTextView extends View {      private static final String TAG = "MyTextView";        private static final boolean DEBUG = false;        private String titleText = "Hello world";        private int titleColor = Color.BLACK;        private int titleBackgroundColor = Color.WHITE;        private int titleSize = 16;        private Paint mPaint;        private Rect mBound;        public MyTextView(Context context) {            this(context, null);        }        public MyTextView(Context context, AttributeSet attrs) {            this(context, attrs, 0);        }        public MyTextView(Context context, AttributeSet attrs, int defStyleAttr) {            super(context, attrs, defStyleAttr);            final Resources.Theme theme = context.getTheme();            TypedArray attrArray = theme.obtainStyledAttributes(attrs,                    R.styleable.MyTextView, defStyleAttr, 0);            if (null != attrArray) {                int conunt = attrArray.getIndexCount();                for (int i = 0; i < conunt; i++) {                    int attr = attrArray.getIndex(i);                    switch (attr) {                        case R.styleable.MyTextView_titleColor:                            titleColor = attrArray.getColor(attr, Color.BLACK);                            break;                        case R.styleable.MyTextView_titleSize:                            titleSize = attrArray.getDimensionPixelSize(attr, titleSize);                            break;                        case R.styleable.MyTextView_titleText:                            titleText = attrArray.getString(attr);                            break;                        case R.styleable.MyTextView_titleBackgroundColor:                            titleBackgroundColor = attrArray.getColor(attr, Color.WHITE);                            break;                    }                }                attrArray.recycle();                init();            }        }        /**         * 初始化         */        private void init() {            mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);            mPaint.setTextSize(titleSize);            /**             * 得到自定义View的titleText内容的宽和高             */            mBound = new Rect();            mPaint.getTextBounds(titleText, 0, titleText.length(), mBound);        }        @Override        protected void onDraw(Canvas canvas) {            mPaint.setColor(titleBackgroundColor);            canvas.drawCircle(getWidth() / 2f, getWidth() / 2f, getWidth() / 2f, mPaint);            mPaint.setColor(titleColor);            canvas.drawText(titleText, getWidth() / 2 - mBound.width() / 2, getHeight() / 2 + mBound.height() / 2, mPaint);        }        @Override        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {            /**             * 测量模式             */            int widthMode = MeasureSpec.getMode(widthMeasureSpec);            /**             * 父布局希望子布局的大小,如果布局里面设置的是固定值,这里取布局里面的固定值和父布局大小值中的最小值.             * 如果设置的是match_parent,则取父布局的大小             */            int widthSize = MeasureSpec.getSize(widthMeasureSpec);            int heightMode = MeasureSpec.getMode(heightMeasureSpec);            int heightSize = MeasureSpec.getSize(heightMeasureSpec);            int width;            int height;            Rect mBounds = new Rect();            /**             *  MeasureSpec.EXACTLY：父视图希望子视图的大小是specSize中指定的大小；一般是设置了明确的值或者是MATCH_PARENT                MeasureSpec.AT_MOST：子视图的大小最多是specSize中的大小；表示子布局限制在一个最大值内，一般为WARP_CONTENT                MeasureSpec.UNSPECIFIED：父视图不对子视图施加任何限制，子视图可以得到任意想要的大小；表示子布局想要多大就多大，很少使用。             */            if (widthMode == MeasureSpec.EXACTLY) {                width = widthSize;            } else {                mPaint.setTextSize(titleSize);                mPaint.getTextBounds(titleText, 0, titleText.length(), mBounds);                float textWidth = mBounds.width();                int desired = (int) (getPaddingLeft() + textWidth + getPaddingRight());                width = desired;            }            if (heightMode == MeasureSpec.EXACTLY) {                height = heightSize;            } else {                height = width;            }            /**             * 最后调用父类方法,把View的大小告诉父布局。             */            setMeasuredDimension(width, height);        }}

自定义文件的引用

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"     xmlns:custom="http://schemas.android.com/apk/res-auto"    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=".MainActivity" >    <com.example.mytextview.MyTextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        custom:titleColor="@android:color/black"        custom:titleSize="25sp"        custom:titleBackgroundColor="#ff0000"        custom:titleText="自定义的View" /></RelativeLayout>xmlns后边的custom这个名字可以任意取，属性设置就是使用这个名字开头。

效果图