自定义recyclerView实现时光轴效果

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发布于 2022-06-22 09:51:22

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发布于 2022-06-22 09:51:22

文章被收录于专栏：深入理解Android

时光轴效果在很多app上都有出现，例如淘宝中快递的跟踪，本文将使用recyclerView实现时光轴效果，我们会到自定义控件，首先先看一下效果图：

接下来是步骤分析

1自定义属性

这个大家应该都了解了，根据我们之前的分析，直接在attrs.xml中进行声明

<declare-styleable name="TimeLine">
    <attr name="beginLine" format="reference|color"></attr>
    <attr name="endLine" format="reference|color"></attr>
    <attr name="lineWidth" format="dimension"></attr>
    <attr name="timeLineImage" format="color|reference"></attr>
    <attr name="timeLineImageSize" format="dimension"></attr>
</declare-styleable>

进行一下各个属性的声明

• beginLine:开始的线条

• endLine:下面的线条

• lineWidth:线条的宽度

• timeLineImage:中间的圆形

• timeLineImageSize:中间的圆形的大小，这里默认他的宽高一致

2.自定义TimeLine继承View，构造方法如下

private int lineWidth;
private Drawable mBeginLine;
private Drawable mEndLine;
private Drawable mTimeLineImage;
private int mTimeLineImageSize;

public TimeLine(Context context) {
    this(context,null);
}

public TimeLine(Context context, AttributeSet attrs) {
    this(context,attrs,0);
}

public TimeLine(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.TimeLine);
    lineWidth = a.getDimensionPixelOffset(R.styleable.TimeLine_lineWidth,15);
    mBeginLine = a.getDrawable(R.styleable.TimeLine_beginLine);
    mEndLine = a.getDrawable(R.styleable.TimeLine_endLine);
    mTimeLineImage = a.getDrawable(R.styleable.TimeLine_timeLineImage);
    mTimeLineImageSize = a.getDimensionPixelSize(R.styleable.TimeLine_timeLineImageSize,25);
    a.recycle();

}

3.复写onMeasure方法

我们都知道自定义控件，一般需要重写onMeasure，onDraw,onLayout方法,这里onMeasure需要对wrap_content的情况进行特殊处理，具体原因请看源码

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int w = timeLineMarkerSize + getPaddingLeft() + getPaddingRight();
        int h = timeLineMarkerSize + getPaddingTop() + getPaddingBottom();
        int widthSize = resolveSizeAndState(w, widthMeasureSpec, 0);
        int heightSize = resolveSizeAndState(h, heightMeasureSpec, 0);
       
        int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSpecSize = MeasureSpec.getSize(heightMeasureSpec);

        // 处理宽高都为 wrap_content 的情况
        if (widthSpecMode == MeasureSpec.AT_MOST && heightSpecMode == MeasureSpec.AT_MOST) {
            setMeasuredDimension(DEFAULT_WIDTH, DEFAULT_HEIGHT);
        }
        // 处理宽为 wrap_content 的情况
        else if (widthSpecMode == MeasureSpec.AT_MOST) {
            setMeasuredDimension(DEFAULT_WIDTH, widthSize);
        }
        // 处理高为 wrap_content 的情况
        else if (heightSpecMode == MeasureSpec.AT_MOST) {
            setMeasuredDimension(heightSize, DEFAULT_HEIGHT);
        }
    }

看过View源码的同学应该知道，在控件进行测量的时候，需要根据

specMode来进行具体的操作，View中提供了resolveSizeAndState方法来进行判断，该方法源码如下：

public static int resolveSizeAndState(int size, int measureSpec, int childMeasuredState) {
        int result = size;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize =  MeasureSpec.getSize(measureSpec);
        switch (specMode) {
        case MeasureSpec.UNSPECIFIED:
            result = size;
            break;
        case MeasureSpec.AT_MOST:
            if (specSize < size) {
                result = specSize | MEASURED_STATE_TOO_SMALL;
            } else {
                result = size;
            }
            break;
        case MeasureSpec.EXACTLY:
            result = specSize;
            break;
        }
        return result | (childMeasuredState&MEASURED_STATE_MASK);
    }

4.onDraw方法

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if (mBeginLine != null) {
        mBeginLine.draw(canvas);
    }
    if (mEndLine != null) {
        mEndLine.draw(canvas);
    }

    if (mTimeLineImage!=null){
        mTimeLineImage.draw(canvas);
    }
}

5.onSizeChange

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    int paddingLeft = getPaddingLeft();
    int paddingRight = getPaddingRight();
    int paddingTop = getPaddingTop();
    int paddingBottom = getPaddingBottom();
    //父容器的宽高
    int width = getWidth();
    int height = getHeight();

    int childWidth = width - paddingLeft - paddingRight;
    int childHeight = height - paddingTop - paddingBottom;

    mTimeLineImageSize = Math.min(mTimeLineImageSize, Math.min(childHeight, childWidth));
    if (mTimeLineImage != null) {
        mTimeLineImage.setBounds(paddingLeft, paddingTop, paddingLeft + mTimeLineImageSize, paddingTop + mTimeLineImageSize);
        bounds = mTimeLineImage.getBounds();
    } else {
        bounds = new Rect(paddingLeft, paddingTop, paddingLeft + childWidth, paddingTop + childHeight);
    }

    if (mBeginLine != null) {
        int lineLeft = mTimeLineImage.getBounds().centerX() - (lineWidth >> 1);
        mBeginLine.setBounds(lineLeft, 0, lineLeft + lineWidth, mTimeLineImage.getBounds().top);
    }
    if (mEndLine != null) {
        int lineLeft = mTimeLineImage.getBounds().centerX() - (lineWidth >> 1);
        mEndLine.setBounds(lineLeft, mTimeLineImage.getBounds().bottom, lineLeft + lineWidth, height);

    }
}

这里需要说明的是，我们的mBeginLine的长度，其实是我们自定义控件的paddingTop高度，同理mEndLine的长度是paddingBottom高度，所以我们在使用这个控件时，一般都会设置paddingTop和paddingBottom

6.使用TimeLine控件

以下是recyclerView中一个item的布局，多个item拼接起来就是一条时光轴，这里需要说明的是，我们的 LinearLayout使用的高度模式是wrap_content，这里我的TextView设置了android:paddingTop="30dp"，如果不对TextView设置android:paddingTop，会发现TimeLineView控件是看不见的，这是由于父控件wrap_content，那么父控件包裹TextView的内容，那么父控件的高度就是TextView的高度，这样TimeLineView设置了android:paddingTop="34dp"，这个高度是大于父控件的高度的，所以就看不到TimeLineView了，除非我们给LinearLayout的android:layout_height="wrap_content"，修改成固定的高度

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:paddingLeft="16dp"
    android:paddingRight="16dp">

    <com.example.jikeyoujikeyou.timelinedemo2.TimeLineView
        android:id="@+id/timeLineView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:clickable="true"
        android:focusable="true"
        android:focusableInTouchMode="true"
        android:paddingBottom="8dp"
        android:paddingLeft="4dp"
        android:paddingRight="4dp"
        android:paddingTop="34dp"
        app:beginLine="#ff0000"
        app:endLine="#ff0000"
        app:lineWidth="3dp"
        app:timeLineMarker="@drawable/timeline_marker"
        app:timeLineMarkerSize="24dp" />


  <TextView
        style="@style/Base.TextAppearance.AppCompat.Title"
        android:id="@+id/timeLineName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ellipsize="end"
        android:paddingTop="30dp"
        android:singleLine="true"
        android:text="name"
        android:textColor="@color/grey_700"
        android:textSize="16sp" />
</LinearLayout>

7.最后就是recyclerView的使用

recyclerView的使用大家应该都很熟悉了，无非就是设置adapter,viewHolder等，这里不再赘述，还有一点需要强调的是ItemViewType有四种情况，第一个，最后一个，中间，还有只有一个四种情况情况，根据这几种情况，有选择设置mBeginLine与 mEndLine是否进行绘制

TimeLineAdapter代码：

package com.example.jikeyoujikeyou.timelinedemo;

import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

/**
 * Created by jikeyoujikeyou on 16/7/22.
 */
public class TimeLineAdapter extends RecyclerView.Adapter<TimeLineAdapter.ViewHolder> {
    private List<TimeLineItem> datas ;

   public TimeLineAdapter(List<TimeLineItem> datas) {
        super();
        this.datas = datas;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
        View view = layoutInflater.inflate(R.layout.item_timeline, null);
        return new ViewHolder(view, parent.getContext(), viewType);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        TimeLineItem timeLineItem = datas.get(position);
        holder.tv_name.setText(timeLineItem.getTimeLineName());
    }

    @Override
    public int getItemCount() {
        return datas.size();
    }

    @Override
    public int getItemViewType(int position) {
        int size = datas.size() - 1;
        if (size == 0) {
            return TimeLineItemType.ATOM;
        } else if (position == 0) {
            return TimeLineItemType.START;
        } else if (position == size) {
            return TimeLineItemType.END;
        } else {
            return TimeLineItemType.NORMAL;
        }

    }

    class ViewHolder extends RecyclerView.ViewHolder {


        private TextView tv_name;
        private TimeLine timeLine;

        public ViewHolder(View itemView, Context context, int viewType) {
            super(itemView);
            tv_name = (TextView) itemView.findViewById(R.id.name);
            timeLine = (TimeLine) itemView.findViewById(R.id.timeLineView);

            Drawable drawable = context.getResources().getDrawable(R.drawable.timeline_marker);
            Drawable drawable2 = context.getResources().getDrawable(R.drawable.timeline_marker2);
            Drawable drawable3 = context.getResources().getDrawable(R.drawable.timeline_marker3);
            Drawable drawable4 = context.getResources().getDrawable(R.drawable.timeline_marker4);
            Drawable drawable5 = context.getResources().getDrawable(R.drawable.timeline_marker5);

            Random random = new Random();
            final int i = random.nextInt(5);
            final Drawable drawables[] = {drawable, drawable2, drawable3, drawable4, drawable5};

            timeLine.setTimeLineImage(drawables[i]);

            if (viewType == TimeLineItemType.START) {
                timeLine.setBeginLine(null);

            } else if (viewType == TimeLineItemType.END) {
                timeLine.setEndLine(null);
            } else if (viewType == TimeLineItemType.ATOM) {
                timeLine.setBeginLine(null);
                timeLine.setEndLine(null);
            }
        }
    }

    class TimeLineItemType {
        //正常
        public final static int NORMAL = 0;
        //开始
        public final static int START = 1;
        //结束
        public final static int END = 2;
        //只有一条数据,那么beginLine和endLine都没有
        public final static int ATOM = 3;
    }

}

MainActivity代码：

<pre name="code" class="java">public class MainActivity extends AppCompatActivity {

    private List<TimeLineItem> mDatas;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initData();
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(linearLayoutManager);
        TimeLineAdapter adapter = new TimeLineAdapter(mDatas);
        recyclerView.setAdapter(adapter);


    }

    private void initData() {
        mDatas = new ArrayList<>();
        mDatas.add(new TimeLineItem("爸爸生日"));
        mDatas.add(new TimeLineItem("妈妈生日"));
        mDatas.add(new TimeLineItem("姐姐生日"));
        mDatas.add(new TimeLineItem("女神生日"));
        mDatas.add(new TimeLineItem("前任生日"));

    }
}

运行项目，就会呈现本文一开始的效果

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原始发表：2016-07-24，如有侵权请联系 cloudcommunity@tencent.com 删除

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