本文主要是介绍可变长度的刻度尺，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
先看效果图
1.先讲下思路，先用xml写单个刻度然后用适配器加载，并设置刻
1. xml
ruler_unit_horizontal.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#00000000"> <FrameLayout android:id="@+id/ruler_frame" android:layout_width="@dimen/dimen_dp_20" android:layout_height="@dimen/dimen_dp_25" android:paddingBottom="@dimen/dimen_dp_4" android:orientation="vertical"> <TextView android:id="@+id/ruler_num" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:paddingBottom="@dimen/dimen_dp_4" android:text="250" android:textColor="@color/white" android:textSize="@dimen/dimen_sp_6" /> <LinearLayout android:id="@+id/ruler_linear" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal|bottom" android:orientation="horizontal"> <View android:id="@+id/ruler_img" android:layout_width="@dimen/dimen_dp_1" android:layout_height="@dimen/dimen_dp_7" android:layout_gravity="bottom|center_horizontal" android:background="@color/white" android:scaleType="fitXY" /> </LinearLayout> <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="bottom|right"> <View android:layout_width="@dimen/dimen_dp_1" android:layout_height="@dimen/dimen_dp_4" android:layout_gravity="bottom" android:background="@color/white" android:scaleType="fitXY" /> </LinearLayout> </FrameLayout> </RelativeLayout> 2.适配器RulerAdapterpublic class RulerAdapter extends RecyclerView.Adapter<RulerAdapter.RulerViewHolder> {private String TAG = "RulerAdapter";public void setList(int list) {this.list = list;notifyDataSetChanged();}private int list = 350;private Context context;private int width;public RulerAdapter(Context context) {this.context = context;}@Override public RulerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {View view = LayoutInflater.from(context).inflate(R.layout.ruler_unit_horizontal, null);return new RulerViewHolder(view);}@Override public void onBindViewHolder(RulerViewHolder holder, int position) {TextView tv = holder.numberView;View view = holder.rulerView;FrameLayout frameLayout = holder.frameLayout;if (frameLayout != null) {if (position == 0) {tv.setText(0 + "");}else {float number=(float)position*5/10;tv.setText(number+"");}}}@Override public int getItemCount() {return list;}class RulerViewHolder extends RecyclerView.ViewHolder {TextView numberView;View rulerView;FrameLayout frameLayout;public RulerViewHolder(View arg0) {super(arg0);numberView = (TextView) arg0.findViewById(R.id.ruler_num);rulerView = (View) arg0.findViewById(R.id.ruler_img);frameLayout = (FrameLayout) arg0.findViewById(R.id.ruler_frame);}} }3.自定义 RecyclerViewpublic class RulerView extends RecyclerView {private static final String TAG = "RulerView";RulerViewListener rulerViewListener = null;@Override public RulerAdapter getAdapter() {return adapter;}RulerAdapter adapter;public void setRulerViewListener(RulerViewListener rulerViewListener) {this.rulerViewListener = rulerViewListener;}public interface RulerViewListener {void onScrollChanged(int l, int t);/** * 是否拖拽 * @param isDraggingMove */ void stateChanged(boolean isDraggingMove);}public RulerView(Context context, @Nullable AttributeSet attrs) {super(context, attrs);if (!isInEditMode()) {TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.RulerView);setLayoutParams(new LayoutParams(1000, LayoutParams.MATCH_PARENT));ta.recycle();init(context);}addScrollListener();}LinearLayoutManager manager;private void init(Context context) {manager = new LinearLayoutManager(context);manager.setOrientation(LinearLayoutManager.HORIZONTAL);setLayoutManager(manager);adapter = new RulerAdapter(context);setAdapter(adapter);manager.scrollToPositionWithOffset(0, 0);}public void scrollToOffset(int x, int y) {if (x<0) {return;}Log.d(TAG, "child scrollToOffset dx: " +x +"-dy-->"+y);manager.scrollToPositionWithOffset(x,y);}@Override public void onScrollStateChanged(int state) {super.onScrollStateChanged(state);if (state==SCROLL_STATE_DRAGGING) {rulerViewListener.stateChanged(true);}else {rulerViewListener.stateChanged(false);}}@Override protected void onScrollChanged(int l, int t, int oldl, int oldt) {super.onScrollChanged(l, t, oldl, oldt);// l=getDistance(); // rulerViewListener.onScrollChanged(l,t); Log.d(TAG, "child onScrollChanged dx: " +l +"-dy-->"+t);}//记录滚动的总距离，类似view中的mScrollX和mScrollY private int sx = 0, sy = 0;//自己定义的滚动监听接口 public interface RecyclerScrollChangeListener{void ScrollChange(int y);}private RecyclerScrollChangeListener mScrollListener = null;//重写scrollTo方法，通过内部的scrollBy实现scrollTo的功能 @Override public void scrollTo(int x, int y) {super.scrollTo(x, y);//计算滚动的相对距离，通过传进来的x和当前的sx差值就是scrollBy需要滚动的值 scrollBy(x - sx, y - sy);}private void addScrollListener(){addOnScrollListener(new OnScrollListener() {@Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) {//因为dx和dy是相对上次的滚动距离，所以通过一开始的累加可以得到总的sx和sy sx += dx;sy += dy;super.onScrolled(recyclerView, dx, dy);rulerViewListener.onScrollChanged(sx,sy);//此处如果有需要监听滚动变化的话在这回调 Log.d(TAG, "child onScrollChanged dx: " +sx +"-dy-->"+sy);}});}}
4. 使用
直接在对应的veiw中添加即可<skill.example.com.skillcreator.skill.view.rulerview.RulerView android:id="@+id/skill_rulerview" android:layout_width="match_parent" android:layout_height="@dimen/dimen_dp_22" android:background="#00000000" />
5.扩展与使用
根据个人项目的应用场景对其进行修改，如xml中一个刻度单元长度进行设置，并且增加小刻度个数，刻度位置等，
并且在代码中动态设置刻度尺的长度，监听当前滑动位置等
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