/**
 * 驗(yàn)證碼輸入框,重寫EditText的繪制方法實(shí)現(xiàn)。
 * @author RAE
 */
public class CodeEditText extends AppCompatEditText {
 
 // 驗(yàn)證碼文本顏色
 private int mTextColor;
 // 輸入的最大長(zhǎng)度
 private int mMaxLength = 4;
 // 邊框?qū)挾?
 private int mStrokeWidth;
 // 邊框高度
 private int mStrokeHeight;
 // 邊框之間的距離
 private int mStrokePadding = 20;
 // 用矩形來保存方框的位置、大小信息
 private final Rect mRect = new Rect();
 // 方框的背景
 private Drawable mStrokeDrawable;

 /**
 * 構(gòu)造方法
 *
 */
 public CodeEditText(Context context, AttributeSet attrs) {
 super(context, attrs);
 TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.CodeEditText);
 int indexCount = typedArray.getIndexCount();
 for (int i = 0; i < indexCount; i++) {
  int index = typedArray.getIndex(i);
  if (index == R.styleable.CodeEditText_strokeHeight) {
  this.mStrokeHeight = (int) typedArray.getDimension(index, 60);
  } else if (index == R.styleable.CodeEditText_strokeWidth) {
  this.mStrokeWidth = (int) typedArray.getDimension(index, 60);

  } else if (index == R.styleable.CodeEditText_strokePadding) {
  this.mStrokePadding = (int) typedArray.getDimension(index, 20);

  } else if (index == R.styleable.CodeEditText_strokeBackground) {
  this.mStrokeDrawable = typedArray.getDrawable(index);

  } else if (index == R.styleable.CodeEditText_strokeLength) {
  this.mMaxLength = typedArray.getInteger(index, 4);
  }
 }
 typedArray.recycle();

 if (mStrokeDrawable == null) {
  throw new NullPointerException("stroke drawable not allowed to be null!");
 }

 setMaxLength(mMaxLength);
 setLongClickable(false);
 // 去掉背景顏色
 setBackgroundColor(Color.TRANSPARENT);
 // 不顯示光標(biāo)
 setCursorVisible(false);
 }

 @Override
 public boolean onTextContextMenuItem(int id) {
 return false;
 }

 /**
 * 設(shè)置最大長(zhǎng)度
 */
 private void setMaxLength(int maxLength) {
 if (maxLength >= 0) {
  setFilters(new InputFilter[]{new InputFilter.LengthFilter(maxLength)});
 } else {
  setFilters(new InputFilter[0]);
 }
 }
}

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 // 當(dāng)前輸入框的寬高信息
 int width = getMeasuredWidth();
 int height = getMeasuredHeight();
 int widthMode = MeasureSpec.getMode(widthMeasureSpec);
 int heightMode = MeasureSpec.getMode(heightMeasureSpec);

 // 判斷高度是否小于推薦高度
 if (height < mStrokeHeight) {
  height = mStrokeHeight;
 }

 // 輸入框?qū)挾?= 邊框?qū)挾?* 數(shù)量 + 邊框間距 *(數(shù)量-1)
 int recommendWidth = mStrokeWidth * mMaxLength + mStrokePadding * (mMaxLength - 1);
 // 判斷寬度是否小于推薦寬度
 if (width < recommendWidth) {
  width = recommendWidth;
 }

 widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, widthMode);
 heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, heightMode);
 // 設(shè)置測(cè)量布局
 setMeasuredDimension(widthMeasureSpec, heightMeasureSpec);
 }

 @Override
 protected void onDraw(Canvas canvas) {
  // 在畫支持設(shè)置文本顏色，把系統(tǒng)化的文本透明掉，相當(dāng)于覆蓋
  mTextColor = getCurrentTextColor();
  setTextColor(Color.TRANSPARENT);
  // 系統(tǒng)畫的方法
  super.onDraw(canvas);
  // 重新設(shè)置文本顏色
  setTextColor(mTextColor);
  // 重繪背景顏色
  drawStrokeBackground(canvas);
  // 重繪文本
  drawText(canvas);
 }

 /**
  * 繪制方框
  */
 private void drawStrokeBackground(Canvas canvas) {
  // 下面繪制方框背景顏色
  // 確定反饋位置
  mRect.left = 0;
  mRect.top = 0;
  mRect.right = mStrokeWidth;
  mRect.bottom = mStrokeHeight;
  int count = canvas.getSaveCount(); // 當(dāng)前畫布保存的狀態(tài)
  canvas.save(); // 保存畫布
  for (int i = 0; i < mMaxLength; i++) {
   mStrokeDrawable.setBounds(mRect); // 設(shè)置位置
   mStrokeDrawable.setState(new int[]{android.R.attr.state_enabled}); // 設(shè)置圖像狀態(tài)
   mStrokeDrawable.draw(canvas); // 畫到畫布上
   // 確定下一個(gè)方框的位置
   float dx = mRect.right + mStrokePadding; // X坐標(biāo)位置
   // 保存畫布
   canvas.save();
   // [注意細(xì)節(jié)] 移動(dòng)畫布到下一個(gè)位置
   canvas.translate(dx, 0);
  }
  // [注意細(xì)節(jié)] 把畫布還原到畫反饋之前的狀態(tài)，這樣就還原到最初位置了
  canvas.restoreToCount(count);
  // 畫布?xì)w位
  canvas.translate(0, 0);

  // 下面繪制高亮狀態(tài)的邊框
  // 當(dāng)前高亮的索引
  int activatedIndex = Math.max(0, getEditableText().length());
  mRect.left = mStrokeWidth * activatedIndex + mStrokePadding * activatedIndex;
  mRect.right = mRect.left + mStrokeWidth;
  mStrokeDrawable.setState(new int[]{android.R.attr.state_focused});
  mStrokeDrawable.setBounds(mRect);
  mStrokeDrawable.draw(canvas);
 }

 /**
  * 重繪文本
  */
 private void drawText(Canvas canvas) {
  int count = canvas.getSaveCount();
  canvas.translate(0, 0);
  int length = getEditableText().length();
  for (int i = 0; i < length; i++) {
   String text = String.valueOf(getEditableText().charAt(i));
   TextPaint textPaint = getPaint();
   textPaint.setColor(mTextColor);
   // 獲取文本大小
   textPaint.getTextBounds(text, 0, 1, mRect);
   // 計(jì)算(x,y) 坐標(biāo)
   int x = mStrokeWidth / 2 + (mStrokeWidth + mStrokePadding) * i - (mRect.centerX());
   int y = canvas.getHeight() / 2 + mRect.height() / 2;
   canvas.drawText(text, x, y, textPaint);
  }
  canvas.restoreToCount(count);
 }

 @Override
 protected void onTextChanged(CharSequence text, int start,
         int lengthBefore, int lengthAfter) {
  super.onTextChanged(text, start, lengthBefore, lengthAfter);

  // 當(dāng)前文本長(zhǎng)度
  int textLength = getEditableText().length();

  if (textLength == mMaxLength) {
   hideSoftInput();
   if (mOnInputFinishListener != null) {
    mOnInputFinishListener.onTextFinish(getEditableText().toString(), mMaxLength);
   }
  }

 }