Android自定义view

一、自定义属性
1、在values文件夹下新建attrs.xml文件
2、自定义属性name：名字，format:类型

<resources>    <attr name="mText" format="string"></attr>    <attr name="textSize" format="dimension"></attr>    <attr name="textColor" format="color"></attr>    <declare-styleable name="CustomText">        <attr name="mText"></attr>        <attr name="textSize"></attr>        <attr name="textColor"></attr>    </declare-styleable></resources>

3、在布局文件中使用自定义控件及属性
注意：要加入 xmlns:app=”http://schemas.android.com/apk/res-auto” 方可使用自定义属性。“app”可以替换成自己的命名。

<com.clkj.customerview.CustomText        android:layout_width="300dp"        android:layout_height="200dp"        app:mText="1234"        app:textColor="#ff0000"        app:textSize="19dp"/>

二、自定义控件
1、新建CustomText类继承自View 具体代码如下
onDraw方法中进行绘制，onMeasure测量控件大小（本质是最终将测量得到的宽高值传递到setMeasuredDimension()中），onLayout方法进行布局（一般继承ViewGroup需要实现此方法来确定子控件的位置）

public class CustomText extends View {    private Paint mPaint;    private int count;    private Rect mBounds;    private String mText;    private int color;    private float size;    public CustomText(Context context) {        this(context,null);    }    public CustomText(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public CustomText(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.CustomText, defStyleAttr, 0);//要使用obtainStyledAttributes四个参数的方法获得自定义属性        int count = ta.getIndexCount();        for(int i = 0;i<count;i++){            int attr = ta.getIndex(i);            switch (attr){                case R.styleable.CustomText_mText:                    mText = ta.getString(attr);                    break;                case R.styleable.CustomText_textColor:                    color = ta.getColor(i,Color.BLUE);                    break;                case R.styleable.CustomText_textSize:                    size = ta.getDimension(i,15);                    break;            }        }        ta.recycle();        mPaint = new Paint();        mBounds = new Rect();        mPaint.getTextBounds(mText,0,mText.length(),mBounds);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        mPaint.setColor(Color.YELLOW);        canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint);        mPaint.setColor(color);        mPaint.setTextSize(size);        canvas.drawText(mText,getMeasuredWidth()/2-mBounds.width()/2,getMeasuredHeight()/2+mBounds.height()/2,mPaint);    }}@Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, 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;        mPaint.setTextSize(size);        mPaint.getTextBounds(mText,0,mText.length(),mBounds);        if(widthMode == MeasureSpec.EXACTLY){            width = widthSize;        }else{            int textWidth = mBounds.width();            width = getPaddingLeft() + textWidth + getPaddingRight();        }        if(heightMode == MeasureSpec.EXACTLY){            height = heightSize;        }else{            height = getPaddingTop() + mBounds.height() + getPaddingBottom();        }        setMeasuredDimension(width,height);    }