Android 自定义属性（点击生成随机数）

Dear 丶 2022-06-07 00:11 238阅读 0赞

**布局文件**

<?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"
        xmlns:openxu="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="com.bwie.test.myview.MainActivity">
    
        <com.bwie.test.myview.MyView
            android:layout_width="200dip"
            android:layout_height="100dip"
            openxu:mTextSize="25sp"
            openxu:mText="自定义属性"
            openxu:mTextColor="#0000ff"
            android:background="#f00"
            />
    </RelativeLayout>
     
     别忘了写这句，否则不可以调用自定义的属性值 xmlns:openxu="http://schemas.android.com/apk/res-auto" 
    
    
     
     在Values文件夹下创建attrs.xml文件 <?xml version="1.0" encoding="utf-8"?>
    <resources>
        <attr name="mText" format="string"/>
        <attr name="mTextColor" format="color" />
        <attr name="mTextSize" format="dimension" />
        <declare-styleable name="MyView">
            <attr name="mText"/>
            <attr name="mTextColor"/>
            <attr name="mTextSize"/>
        </declare-styleable>
    
    </resources>
     
     自定义Class类继承View，实现的代码：
     
     
     public class MyView extends View{
    
        /*文字*/
        private String mText;
        private int mTextColor;
        private int mTextSize;
    //    绘制文本范围
        private Rect mbound;
        private Paint mPaint;
    
        public MyView(Context context) {
            this(context,null);
        }
    
        public MyView(Context context, AttributeSet attrs) {
            this(context, attrs,0);
        }
    
        /*构造方法里边实例化画笔*/
        public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
        /*  //  自定义布局
            mText="文字";
            mTextColor= Color.BLACK;
            mTextSize=100;
    
            mPaint = new Paint();
            mPaint.setTextSize(mTextSize);
            mPaint.setColor(mTextColor);
            *//* 获得绘制文本的宽s和高*//*
            mbound = new Rect();
            mPaint.getTextBounds(mText,0,mText.length(),mbound);*/
    
            //获取自定义属性的值
            TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.MyView, defStyleAttr, 0);
            mText=a.getString(R.styleable.MyView_mText);
            mTextColor=a.getColor(R.styleable.MyView_mTextColor,Color.BLACK);
    //        mTextSize=(int) a.getDimension(R.styleable.MyView_mTextSize,100); // int,float----可以强转为int
            mTextSize=a.getDimensionPixelSize(R.styleable.MyView_mTextSize,100);  //int ,int
            a.recycle();//回收
            mPaint = new Paint();
            mPaint.setTextSize(mTextSize);
            mPaint.setColor(mTextColor);
    //        获得绘制文本的宽和高
            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);
        }
    
        /*测量*/
        @Override
        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        }
    
        /*绘制*/
        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            /* 绘制文字*/
            canvas.drawText(mText,getWidth()/2-mbound.width()/2,getHeight()/2-mbound.height()/2,mPaint);
        }
    
        //定位
        @Override
        protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
            super.onLayout(changed, left, top, right, bottom);
        }
    
        /*点击*/
        @Override
        public boolean onTouchEvent(MotionEvent event) {
    
            switch (event.getAction()){
                case MotionEvent.ACTION_MOVE:
                    break;
                case MotionEvent.ACTION_DOWN:
                    /*随机数*/
                    float a=(float) (Math.random()*10000);
                    mText=""+a;
                    invalidate(); //更新视图
                    break;
                case MotionEvent.ACTION_UP:
                    Log.d("main","抬起");
                    break;
            }
            return super.onTouchEvent(event);
        }
    最后的效果图