Android自定义View实现垂直时间轴布局

时间轴

时间轴，顾名思义就是将发生的事件按照时间顺序罗列起来，给用户带来一种更加直观的体验。京东和淘宝的物流顺序就是一个时间轴，想必大家都不陌生，如下图：

分析

实现这个最常用的一个方法就是用ListView，我这里用继承LinearLayout的方式来实现。首先定义了一些自定义属性：

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="TimelineLayout">
        <!--时间轴左偏移值-->
        <attr name="line_margin_left" format="dimension"/>
        <!--时间轴上偏移值-->
        <attr name="line_margin_top" format="dimension"/>
        <!--线宽-->
        <attr name="line_stroke_width" format="dimension"/>
        <!--线的颜色-->
        <attr name="line_color" format="color"/>
        <!--点的大小-->
        <attr name="point_size" format="dimension"/>
        <!--点的颜色-->
        <attr name="point_color" format="color"/>
        <!--图标-->
        <attr name="icon_src" format="reference"/>
    </declare-styleable>
</resources>

package com.jackie.timeline;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.widget.LinearLayout;

/**
 * Created by Jackie on 2017/3/8.
 * 时间轴控件
 */

public class TimelineLayout extends LinearLayout {
    private Context mContext;

    private int mLineMarginLeft;
    private int mLineMarginTop;
    private int mLineStrokeWidth;
    private int mLineColor;;
    private int mPointSize;
    private int mPointColor;
    private Bitmap mIcon;

    private Paint mLinePaint;  //线的画笔
    private Paint mPointPaint;  //点的画笔
    

    //第一个点的位置
    private int mFirstX;
    private int mFirstY;
    //最后一个图标的位置
    private int mLastX;
    private int mLastY;

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

    public TimelineLayout(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public TimelineLayout(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.TimelineLayout);
        mLineMarginLeft = ta.getDimensionPixelOffset(R.styleable.TimelineLayout_line_margin_left, 10);
        mLineMarginTop = ta.getDimensionPixelOffset(R.styleable.TimelineLayout_line_margin_top, 0);
        mLineStrokeWidth = ta.getDimensionPixelOffset(R.styleable.TimelineLayout_line_stroke_width, 2);
        mLineColor = ta.getColor(R.styleable.TimelineLayout_line_color, 0xff3dd1a5);
        mPointSize = ta.getDimensionPixelSize(R.styleable.TimelineLayout_point_size, 8);
        mPointColor = ta.getDimensionPixelOffset(R.styleable.TimelineLayout_point_color, 0xff3dd1a5);

        int iconRes = ta.getResourceId(R.styleable.TimelineLayout_icon_src, R.drawable.ic_ok);
        BitmapDrawable drawable = (BitmapDrawable) context.getResources().getDrawable(iconRes);
        if (drawable != null) {
            mIcon = drawable.getBitmap();
        }

        ta.recycle();

        setWillNotDraw(false);
        initView(context);
    }

    private void initView(Context context) {
        this.mContext = context;

        mLinePaint = new Paint();
        mLinePaint.setAntiAlias(true);
        mLinePaint.setDither(true);
        mLinePaint.setColor(mLineColor);
        mLinePaint.setStrokeWidth(mLineStrokeWidth);
        mLinePaint.setStyle(Paint.Style.FILL_AND_STROKE);

        mPointPaint = new Paint();
        mPointPaint.setAntiAlias(true);
        mPointPaint.setDither(true);
        mPointPaint.setColor(mPointColor);
        mPointPaint.setStyle(Paint.Style.FILL);
    }

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

    private void drawTimeline(Canvas canvas) {
        int childCount = getChildCount();

        if (childCount > 0) {
            if (childCount > 1) {
                //大于1，证明至少有2个，也就是第一个和第二个之间连成线，第一个和最后一个分别有点和icon
                drawFirstPoint(canvas);
                drawLastIcon(canvas);
                drawBetweenLine(canvas);
            } else if (childCount == 1) {
                drawFirstPoint(canvas);
            }
        }
    }

    private void drawFirstPoint(Canvas canvas) {
        View child = getChildAt(0);
        if (child != null) {
            int top = child.getTop();
            mFirstX = mLineMarginLeft;
            mFirstY = top + child.getPaddingTop() + mLineMarginTop;

            //画圆
            canvas.drawCircle(mFirstX, mFirstY, mPointSize, mPointPaint);
        }
    }

    private void drawLastIcon(Canvas canvas) {
        View child = getChildAt(getChildCount() - 1);
        if (child != null) {
            int top = child.getTop();
            mLastX = mLineMarginLeft;
            mLastY = top + child.getPaddingTop() + mLineMarginTop;

            //画图
            canvas.drawBitmap(mIcon, mLastX - (mIcon.getWidth() >> 1), mLastY, null);
        }
    }

    private void drawBetweenLine(Canvas canvas) {
        //从开始的点到最后的图标之间，画一条线
        canvas.drawLine(mFirstX, mFirstY, mLastX, mLastY, mLinePaint);
        for (int i = 0; i < getChildCount() - 1; i++) {
            //画圆
            int top = getChildAt(i).getTop();
            int y = top + getChildAt(i).getPaddingTop() + mLineMarginTop;
            canvas.drawCircle(mFirstX, y, mPointSize, mPointPaint);
        }
    }

    public int getLineMarginLeft() {
        return mLineMarginLeft;
    }

    public void setLineMarginLeft(int lineMarginLeft) {
        this.mLineMarginLeft = lineMarginLeft;
        invalidate();
    }
}

activity_main.xml

<?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="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:weightSum="2">

        <Button
            android:id="@+id/add_item"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="add"/>

        <Button
            android:id="@+id/sub_item"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="sub"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:weightSum="2">

        <Button
            android:id="@+id/add_margin"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:text="+"/>

        <Button
            android:id="@+id/sub_margin"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:text="-"/>
    </LinearLayout>

    <TextView
        android:id="@+id/current_margin"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:gravity="center"
        android:text="current line margin left is 25dp"/>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="none">

        <com.jackie.timeline.TimelineLayout
            android:id="@+id/timeline_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:line_margin_left="25dp"
            app:line_margin_top="8dp"
            android:orientation="vertical"
            android:background="@android:color/white">
        </com.jackie.timeline.TimelineLayout>
    </ScrollView>
</LinearLayout>

package com.jackie.timeline;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private Button addItemButton;
    private Button subItemButton;
    private Button addMarginButton;
    private Button subMarginButton;
    private TextView mCurrentMargin;

    private TimelineLayout mTimelineLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
    }

    private void initView() {
        addItemButton = (Button) findViewById(R.id.add_item);
        subItemButton = (Button) findViewById(R.id.sub_item);
        addMarginButton= (Button) findViewById(R.id.add_margin);
        subMarginButton= (Button) findViewById(R.id.sub_margin);
        mCurrentMargin= (TextView) findViewById(R.id.current_margin);
        mTimelineLayout = (TimelineLayout) findViewById(R.id.timeline_layout);

        addItemButton.setOnClickListener(this);
        subItemButton.setOnClickListener(this);
        addMarginButton.setOnClickListener(this);
        subMarginButton.setOnClickListener(this);
    }

    private int index = 0;
    private void addItem() {
        View view = LayoutInflater.from(this).inflate(R.layout.item_timeline, mTimelineLayout, false);
        ((TextView) view.findViewById(R.id.tv_action)).setText("步骤" + index);
        ((TextView) view.findViewById(R.id.tv_action_time)).setText("2017年3月8日16:55:04");
        ((TextView) view.findViewById(R.id.tv_action_status)).setText("完成");
        mTimelineLayout.addView(view);
        index++;
    }

    private void subItem() {
        if (mTimelineLayout.getChildCount() > 0) {
            mTimelineLayout.removeViews(mTimelineLayout.getChildCount() - 1, 1);
            index--;
        }
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.add_item:
                addItem();
                break;
            case R.id.sub_item:
                subItem();
                break;
            case R.id.add_margin:
                int currentMargin = UIHelper.pxToDip(this, mTimelineLayout.getLineMarginLeft());
                mTimelineLayout.setLineMarginLeft(UIHelper.dipToPx(this, ++currentMargin));
                mCurrentMargin.setText("current line margin left is " + currentMargin + "dp");
                break;
            case R.id.sub_margin:
                currentMargin = UIHelper.pxToDip(this, mTimelineLayout.getLineMarginLeft());
                mTimelineLayout.setLineMarginLeft(UIHelper.dipToPx(this, --currentMargin));
                mCurrentMargin.setText("current line margin left is " + currentMargin + "dp");
                break;
            default:
                break;
        }
    }
}

item_timeline.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="wrap_content"
    android:paddingLeft="65dp"
    android:paddingTop="20dp"
    android:paddingRight="20dp"
    android:paddingBottom="20dp">

    <TextView
        android:id="@+id/tv_action"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="14sp"
        android:textColor="#1a1a1a"
        android:text="测试一"/>

    <TextView
        android:id="@+id/tv_action_time"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="12sp"
        android:textColor="#8e8e8e"
        android:layout_below="@id/tv_action"
        android:layout_marginTop="10dp"
        android:text="2017年3月8日16:49:12"/>

    <TextView
        android:id="@+id/tv_action_status"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="14sp"
        android:textColor="#3dd1a5"
        android:layout_alignParentRight="true"
        android:text="完成"/>

</RelativeLayout>

package com.jackie.timeline;

import android.content.Context;

/**
 * Created by Jackie on 2017/3/8.
 */
public final class UIHelper {

    private UIHelper() throws InstantiationException {
        throw new InstantiationException("This class is not for instantiation");
    }

    /**
     * dip转px
     */
    public static int dipToPx(Context context, float dip) {
        return (int) (dip * context.getResources().getDisplayMetrics().density + 0.5f);
    }

    /**
     * px转dip
     */
    public static int pxToDip(Context context, float pxValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }
}