<?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> 

<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/com.example.customview01" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" > 
 
 <com.example.customview01.view.CustomTitleView 
  android:layout_width="200dp" 
  android:layout_height="100dp" 
  custom:titleText="3712" 
  custom:titleTextColor="#ff0000" 
  custom:titleTextSize="40sp" /> 
 
</RelativeLayout> 

/** 
  * 文本 
  */ 
 private String mTitleText; 
 /** 
  * 文本的颜色 
  */ 
 private int mTitleTextColor; 
 /** 
  * 文本的大小 
  */ 
 private int mTitleTextSize; 
 
 /** 
  * 绘制时控制文本绘制的范围 
  */ 
 private Rect mBound; 
 private Paint mPaint; 
 
 public CustomTitleView(Context context, AttributeSet attrs) 
 { 
  this(context, attrs, 0); 
 } 
 
 public CustomTitleView(Context context) 
 { 
  this(context, null); 
 } 
 
 /** 
  * 获得我自定义的样式属性 
  * 
  * @param context 
  * @param attrs 
  * @param defStyle 
  */ 
 public CustomTitleView(Context context, AttributeSet attrs, int defStyle) 
 { 
  super(context, attrs, defStyle); 
  /** 
   * 获得我们所定义的自定义样式属性 
   */ 
  TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomTitleView, defStyle, 0); 
  int n = a.getIndexCount(); 
  for (int i = 0; i < n; i++) 
  { 
   int attr = a.getIndex(i); 
   switch (attr) 
   { 
   case R.styleable.CustomTitleView_titleText: 
    mTitleText = a.getString(attr); 
    break; 
   case R.styleable.CustomTitleView_titleTextColor: 
    // 默认颜色设置为黑色 
    mTitleTextColor = a.getColor(attr, Color.BLACK); 
    break; 
   case R.styleable.CustomTitleView_titleTextSize: 
    // 默认设置为16sp，TypeValue也可以把sp转化为px 
    mTitleTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( 
      TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics())); 
    break; 
 
   } 
 
  } 
  a.recycle(); 
 
  /** 
   * 获得绘制文本的宽和高 
   */ 
  mPaint = new Paint(); 
  mPaint.setTextSize(mTitleTextSize); 
  // mPaint.setColor(mTitleTextColor); 
  mBound = new Rect(); 
  mPaint.getTextBounds(mTitleText, 0, mTitleText.length(), mBound); 
 
 } 

@Override 
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) 
 { 
  super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
 } 
 
 @Override 
 protected void onDraw(Canvas canvas) 
 { 
  mPaint.setColor(Color.YELLOW); 
  canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint); 
 
  mPaint.setColor(mTitleTextColor); 
  canvas.drawText(mTitleText, getWidth() / 2 - mBound.width() / 2, getHeight() / 2 + mBound.height() / 2, mPaint); 
 } 

@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 
 { 
  mPaint.setTextSize(mTitleTextSize); 
  mPaint.getTextBounds(mTitle, 0, mTitle.length(), mBounds); 
  float textWidth = mBounds.width(); 
  int desired = (int) (getPaddingLeft() + textWidth + getPaddingRight()); 
  width = desired; 
 } 
 
 if (heightMode == MeasureSpec.EXACTLY) 
 { 
  height = heightSize; 
 } else 
 { 
  mPaint.setTextSize(mTitleTextSize); 
  mPaint.getTextBounds(mTitle, 0, mTitle.length(), mBounds); 
  float textHeight = mBounds.height(); 
  int desired = (int) (getPaddingTop() + textHeight + getPaddingBottom()); 
  height = desired; 
 } 
  
  
 
 setMeasuredDimension(width, height); 
} 

<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/com.example.customview01" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" > 
 
 <com.example.customview01.view.CustomTitleView 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  custom:titleText="3712" 
  android:padding="10dp" 
  custom:titleTextColor="#ff0000" 
  android:layout_centerInParent="true" 
  custom:titleTextSize="40sp" /> 
 
</RelativeLayout> 

this.setOnClickListener(new OnClickListener() 
  { 
 
   @Override 
   public void onClick(View v) 
   { 
    mTitleText = 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(); 
 }