自定义View和Attr联合使用

1.自定义类

public class CustomTitleView extends View {    private String titleText;    private int color;    private Paint paint;    private int size;    private Rect rect;    public CustomTitleView(Context context) {        this(context,null);    }    public CustomTitleView(Context context, AttributeSet attrs) {        this(context, attrs,0);    }    public CustomTitleView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        //首先获得我们自定义的样式属性        TypedArray typedArray = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomTitleView, defStyleAttr, 0);        int indexCount = typedArray.getIndexCount();        for (int i = 0; i <indexCount ; i++) {            int index = typedArray.getIndex(i);            switch(index){                case R.styleable.CustomTitleView_titleText:                    titleText = typedArray.getString(index);                    break;                case R.styleable.CustomTitleView_titleTextColor:                    color = typedArray.getColor(index, Color.BLACK);                    break;                case R.styleable.CustomTitleView_titleTextSize:                    //默认设置为16sp,TypedValue也可以把sp转换为px                    size = typedArray.getDimensionPixelSize(index, (int) TypedValue.applyDimension(                            TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));                    break;                default:                    break;            }        }        //回收        typedArray.recycle();        //获得绘制文本的宽和高        paint = new Paint();        paint.setTextSize(size);        paint.setColor(color);        //建一个矩形        rect = new Rect();        //得到文本界限        paint.getTextBounds(titleText,0,titleText.length(),rect);        //在构造方法里写点击事件        this.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View view) {                titleText = randomText();                postInvalidate();            }        });    }//    @Override//    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)//    {//        int widthMode = MeasureSpec.getMode(widthMeasureSpec);//        int widthSize = MeasureSpec.getSize(widthMeasureSpec);//        int heightMode = MeasureSpec.getMode(heightMeasureSpec);//        int heightSize = MeasureSpec.getSize(heightMeasureSpec);//        int width;//        int height ;//        if (widthMode == MeasureSpec.EXACTLY)//        {//            width = widthSize;//        } else//        {//            paint.setTextSize(size);//            paint.getTextBounds(titleText, 0, titleText.length(), rect);//            float textWidth = rect.width();//            int desired = (int) (getPaddingLeft() + textWidth + getPaddingRight());//            width = desired;//        }////        if (heightMode == MeasureSpec.EXACTLY)//        {//            height = heightSize;//        } else//        {//            paint.setTextSize(size);//            paint.getTextBounds(titleText, 0, titleText.length(), rect);//            float textHeight = rect.height();//            int desired = (int) (getPaddingTop() + textHeight + getPaddingBottom());//            height = desired;//        }//        setMeasuredDimension(width, height);//    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        paint.setColor(Color.YELLOW);        canvas.drawRect(0,0,getMeasuredWidth(),getMeasuredHeight(),paint);        paint.setColor(color);        canvas.drawText(titleText,getWidth() / 2 - rect.width() / 2, getHeight() / 2 + rect.height() / 2,paint);    }    //随机生成4位数    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();    }}

2.Res/values/attrs.xml

<?xml version="1.0" encoding="utf-8"?><resources>    <attr name="titleText" format="string"/>    <attr name="titleTextColor" format="color"/>    <attr name="titleTextSize" format="dimension"/>    <declare-styleable name="CustomTitleView">        <attr name="titleText"/>        <attr name="titleTextColor"/>        <attr name="titleTextSize"/>    </declare-styleable></resources>

3.MainActivity

<?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"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"   ><com.example.anadministrator.customviewdemo.CustomTitleView    android:layout_width="300dp"    android:layout_height="300dp"    custom:titleText="你好"    custom:titleTextColor="#f00"    android:layout_centerInParent="true"    custom:titleTextSize="30sp"    /></RelativeLayout>