android尺子的自定义view——RulerView详解

public class RuleView extends View {

  private Paint paint;

  private Context context;

  private int maxValue = 500;
  /**
   * 起点x的坐标
   */
  private float startX ;

  private float startY ;
  /**
   * 刻度线的长度
   */
  private float yLenght ;
  /**
   * 刻度的间隙
   */
//  private float gap = 8f;
  private float gap = 10;
  /**
   * 文本的间隙
   */
  private float textGap = 10f;
  /**
   * 短竖线的高度
   */
  private float smallHeight = 10f;
  /**
   * 长竖线的高度
   */
  private float largeHeight = 22f;
  
  /**
   * 文本显示格式化
   */
  private DecimalFormat format;

  private DisplayMetrics metrics = null;
  /**
   * 文本的字体大小
   */
  private float mFontSize;

  private Handler mScrollHandler = null;

  private MyHorizontalScrollView horizontalScrollView;

  private int mCurrentX = -999999999;
  /**
   * 刻度进制
   */
//  private float unit = 10f;
  private int unit = 10;//隔unit个刻度写一个数字
  //每个大刻度代表值iValue
  private int iValue = 10;

  boolean isDraw = true;

  public RuleView(Context context) {
    super(context);
    this.context = context;
    init();
  }

  public void setHorizontalScrollView(
      MyHorizontalScrollView horizontalScrollView) {
    this.horizontalScrollView = horizontalScrollView;

    this.horizontalScrollView.setOnTouchListener(new OnTouchListener() {

      @Override
      public boolean onTouch(View v, MotionEvent event) {

        final int action = event.getAction();
        switch (action) {
        case MotionEvent.ACTION_DOWN:

          break;
        case MotionEvent.ACTION_MOVE:

          mScrollHandler.removeCallbacks(mScrollRunnable);
          break;
        case MotionEvent.ACTION_UP:

          mScrollHandler.post(mScrollRunnable);
          break;
        }
        return false;
      }
    });
  }

  public RuleView(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.context = context;

    init();
  }

  public void init() {

//    format = new DecimalFormat("0.0");
    format = new DecimalFormat("0");//不使用浮点数格式

    metrics = new DisplayMetrics();
    WindowManager wmg = (WindowManager) context
        .getSystemService(Context.WINDOW_SERVICE);
    wmg.getDefaultDisplay().getMetrics(metrics);

    paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    paint.setStyle(Paint.Style.FILL);
    paint.setStrokeWidth(getResources().getDimension(R.dimen.ui_1_dip));
//    paint.setStrokeWidth(2);
    paint.setColor(Color.parseColor("#999999"));

    mFontSize = ScreenUtil.dip2px(context, 16);
//    startY = ScreenUtil.dip2px(context, 20f);
    startY = ScreenUtil.dip2px(context, 0);//Y轴由0开始，即最顶端，不用设置适配布局文件RuleView的android:layout_marginTop="-20dp"
    yLenght = ScreenUtil.dip2px(context, 10);
//    gap = ScreenUtil.dip2px(context, 8f);
    gap = ScreenUtil.dip2px(context, 10);
//    startX = ScreenUtil.getScreenWidth(context)/ 2.0f- getResources().getDimension(R.dimen.ui_10_dip) ;
    startX = ScreenUtil.getScreenWidth(context)/ 2.0f;//X轴不减去10dp，则三角形顶点可以刚好最准0位置

    //   getResources().getDimension(R.dimen.text_h2)/2.0f
    // Util.dip2px(context, 13f)  

    mScrollHandler = new Handler(context.getMainLooper());

  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    float width = maxValue * gap   ScreenUtil.getScreenWidth(context) - getResources().getDimension(R.dimen.ui_10_dip)*2.0f ;

    // int widthMode = MeasureSpec.getMode(heightMeasureSpec);
    // if(widthMode == MeasureSpec.AT_MOST){
    // Log.d("TAG", "mode::AT_MOST");
    // }else if(widthMode == MeasureSpec.EXACTLY){
    // Log.d("TAG", "mode::EXACTLY");
    // }else if(widthMode == MeasureSpec.UNSPECIFIED){
    // Log.d("TAG", "mode::UNSPECIFIED");
    // }

    setMeasuredDimension((int) width, heightMeasureSpec);
  }

  @Override
  protected void onDraw(final Canvas canvas) {
    super.onDraw(canvas);

    // 画刻度线
    paint.setColor(getResources().getColor(R.color.gray_bg_high));// 刻度颜色
    for (int i = 0; i <= maxValue; i  ) {

      if (i % 5 == 0) {
        yLenght = ScreenUtil.dip2px(context, largeHeight);
      } else {
        yLenght = ScreenUtil.dip2px(context, smallHeight);
      }
      canvas.drawLine(i * gap   startX, startY, i * gap   startX, yLenght
            startY, paint);
    }

    paint.setTextSize(mFontSize);

    // 每10个刻度写一个数字
    textGap = gap * unit;

    // 画刻度文字30
    paint.setColor(getResources().getColor(R.color.textGray));// 文字颜色
    for (int i = 0; i <= maxValue / unit; i  ) {

//      String text = format.format(i   1)   "";//从0开始计数时不用加1
      String text = format.format(i * iValue)   "";//乘以每刻度的值iValue
      // 获取文本的宽度
      float width = ScreenUtil.px2dip(context, calculateTextWidth(text)) / 2f;

      canvas.drawText(
          text,
          startX - width   i * textGap,
          (startY   ScreenUtil.dip2px(context, largeHeight))
                ScreenUtil.dip2px(context, 24), paint);//字体大小
    }
  }

  /**
   * 获取TextView中文本的宽度
   */
  private float calculateTextWidth(String text) {
    if (TextUtils.isEmpty(text)) {
      return 0;
    }
    TextPaint textPaint = new TextPaint();
    textPaint.setTextSize(mFontSize * metrics.scaledDensity);
    final float textWidth = textPaint.measureText(text);

    return textWidth;
  }

  DecimalFormat df = new DecimalFormat("0.0");

  /**
   * 当滑动尺子的时候
   */
  int scrollWidth = 0;

  public void setScrollerChanaged(int l, int t, int oldl, int oldt) {
    // 滑动的距离
    scrollWidth = l;

    float number = scrollWidth / gap;
    float result = number / unit;

    listener.onSlide(result);
  }

  public onChangedListener listener;

  public interface onChangedListener {

    void onSlide(float number);
  }

  public void onChangedListener(onChangedListener listener) {
    this.listener = listener;
  }

  /**
   * 滚动监听线程
   */
  private Runnable mScrollRunnable = new Runnable() {

    @Override
    public void run() {
      if (mCurrentX == horizontalScrollView.getScrollX()) {// 滚动停止了

        try {

          float x = horizontalScrollView.getScrollX();
          float value = (x / (gap * unit));// 当前的值
          String s = df.format(value);

          // 滑动到11.0 ok
          int scrollX = (int) (Double.parseDouble(s) * gap * unit);

          horizontalScrollView.smoothScrollTo(scrollX, 0);

        } catch (NumberFormatException numExp) {
          numExp.printStackTrace();
        }
        mScrollHandler.removeCallbacks(this);
      } else {
        mCurrentX = horizontalScrollView.getScrollX();
        mScrollHandler.postDelayed(this, 50);
      }
    }
  };

  /**
   * 设置默认刻度尺的刻度值,不会滚动到相应的位置
   * 
   * @param scaleValue
   */
  public void setDefaultScaleValue(float scaleValue) {

//    final int scrollX = (int) ((scaleValue - 1.0f) * gap * unit);//从0开始计数时不用减去1
    final int scrollX = (int) (scaleValue * gap * unit / 10);//每个值在设置刻度时会乘以10，所以除去

    new Handler().postDelayed(new Runnable() {

      @Override
      public void run() {

        horizontalScrollView.smoothScrollTo(scrollX, 0);
      }
    }, 100);
  }

  /**
   * 设置刻度值
   */
  public void setScaleValue(int iValue) {
    this.iValue = iValue;
  }

  /**
   * 设置刻度最小值
   */
  public void setMinScaleValue(Float minScaleValue) {
    // this.minScaleValue = minScaleValue;
  }

  /**
   * 获取刻度最大值
   */
  public Float getMaxScaleValue() {
    // return maxScaleValue;
    return 33.0f;
  }

  /**
   * 设置刻度最大值
   */
  public void setMaxScaleValue(Float maxScaleValue) {
    // this.maxScaleValue = maxScaleValue;
  }

  /**
   * 设置当前刻度尺的刻度值,并滚动到相应的位置
   * 
   * @param scaleValue
   */
  public void setScaleScroll(float scaleValue) {

    int scrollX = (int) ((scaleValue - 1.0f) * gap * unit);

    horizontalScrollView.smoothScrollTo(scrollX, 0);
  }
}

public class MyHorizontalScrollView extends HorizontalScrollView {

  private OnScrollListener onScrollListener = null;

  public MyHorizontalScrollView(Context context) {
    this(context, null);
  }
  public MyHorizontalScrollView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }
  public MyHorizontalScrollView(Context context, AttributeSet attrs,
      int defStyleAttr) {
    super(context, attrs, defStyleAttr);
  }

  @Override
  protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    super.onScrollChanged(l, t, oldl, oldt);
    if(onScrollListener != null){
      onScrollListener.onScrollChanged(l, t, oldl, oldt);
    }
  }

  public interface OnScrollListener {
    public void onScrollChanged(int l, int t, int oldl, int oldt);
  }

  public void setOnScrollListener(OnScrollListener onScrollListener) {
    this.onScrollListener = onScrollListener;
  }
}

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

  <item android:id="@ id/shape_id">
    <!--&lt;!&ndash; 正三角 &ndash;&gt;-->
    <!--<rotate-->
    <!--android:fromDegrees="45"-->
    <!--android:toDegrees="45"-->
    <!--android:pivotX="-40%"-->
    <!--android:pivotY="80%">-->
    <!-- 倒三角 -->
    <rotate
      android:fromDegrees="45"
      android:toDegrees="45"
      android:pivotX="135%"
      android:pivotY="15%"
      >
      <shape android:shape="rectangle">
        <solid android:color="@color/main_yellow"/>
      </shape>
    </rotate>
  </item>

</layer-list>

<RelativeLayout
      android:layout_width="match_parent"
      android:layout_height="300px"
      android:layout_marginTop="30px"
      android:background="#fff">
    <MyHorizontalScrollView
      android:id="@ id/hor_scrollview"
      android:layout_width="match_parent"
      android:layout_height="300px"
      android:scrollbars="none" >


      <RuleView
        android:id="@ id/rule_view"
        android:background="@color/main_white"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="top"/>
    </MyHorizontalScrollView>
      <View
        android:layout_width="match_parent"
        android:layout_height="1px"
        android:background="@color/gray_bg"
        android:layout_centerHorizontal="true"
        android:layout_alignParentBottom="true" />
      <View
        android:layout_width="30px"
        android:layout_height="30px"
        android:layout_centerHorizontal="true"
        android:layout_alignParentTop="true"
        android:background="@drawable/shape_triangle" />
    </RelativeLayout>

ruleView = (RuleView) findViewById(R.id.rule_view);

    horizontalScrollView = (MyHorizontalScrollView) findViewById(R.id.hor_scrollview);
    horizontalScrollView.setOverScrollMode(View.OVER_SCROLL_NEVER);// 去掉超出滑动后出现的阴影效果

    // 设置水平滑动
    ruleView.setHorizontalScrollView(horizontalScrollView);
    ruleView.setDefaultScaleValue(num);

    // 当滑动尺子的时候
    horizontalScrollView.setOnScrollListener(new MyHorizontalScrollView.OnScrollListener() {

      @Override
      public void onScrollChanged(int l, int t, int oldl, int oldt) {

        ruleView.setScrollerChanaged(l, t, oldl, oldt);
      }
    });


    ruleView.onChangedListener(new RuleView.onChangedListener() {
      @Override
      public void onSlide(float number) {

        int num = (int) (number * 10);
        tvNum.setText(num "");
      }
    });