Android自定义View实现垂直时间轴布局

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>

TimelineLayout.java

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();
}
}

从上面的代码可以看出，分三步绘制，首先绘制开始的实心圆，然后绘制结束的图标，然后在开始和结束之间先绘制一条线，然后在线上在绘制每个步骤的实心圆。
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>

MainActivity.java

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>

附上像素工具转化的工具类：

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);
}
}

效果图如下：