这篇文章主要为大家分析了android自定义控件是怎么实现简易时间轴的相关知识点，内容详细易懂，操作细节合理，具有一定参考价值。如果感兴趣的话，不妨跟着跟随小编一起来看看，下面跟着小编一起深入学习“android自定义控件是怎么实现简易时间轴”的知识吧。
之前项目需要写一个消费记录，类似于时间轴似的控件，自身在自定义控件这里不咋地（…），最后搞了一个这个demo
效果图：
这里就是绘制圆和上下两条线
资源文件，定义一些基本的属性：
<?xml version="1.0" encoding="utf-8"?><resources> <attr name="textSize" format="dimension" /> <attr name="textColor" format="color" /> <attr name="textTitle" format="string" /> <attr name="borderColor" format="color" /> <attr name="borderWidth" format="dimension" /> <attr name="lineColor" format="color" /> <attr name="lineWidth" format="dimension" /> <attr name="bgColor" format="color" /> <attr name="mRadius" format="dimension"/> <declare-styleable name="CustomCicleView"> <attr name="textSize" /> <attr name="textColor" /> <attr name="textTitle" /> <attr name="lineColor" /> <attr name="lineWidth" /> <attr name="bgColor" /> <attr name="borderColor" /> <attr name="borderWidth" /> <attr name="mRadius" /> </declare-styleable></resources>获取属性：
int attr=a.getIndex(i); switch (attr) { case R.styleable.CustomCicleView_textSize: // 默认设置为16sp，TypeValue也可以把sp转化为px mTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_PX, 14, getResources().getDisplayMetrics())); break; case R.styleable.CustomCicleView_textColor: mTextColor=a.getColor(attr, Color.BLACK); break; case R.styleable.CustomCicleView_lineWidth: mLineWidth= a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_PX, 2, getResources().getDisplayMetrics())); break; case R.styleable.CustomCicleView_lineColor: mLineColor=a.getColor(attr, lineColr); break; case R.styleable.CustomCicleView_borderWidth: mBorderWidth= a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_PX, 2, getResources().getDisplayMetrics())); break; case R.styleable.CustomCicleView_borderColor: mBorderColor=a.getColor(attr, borderColor); break; case R.styleable.CustomCicleView_bgColor: mBgColor=a.getColor(attr, bgColor); break; }这里主要释放资源方便回收：
a.recycle();//官方API的解释是：给回一个先前的提取的数组，为以后复用,，就是当前的对象回收，下次要用的时候就不用重新再new一个新的对象了，直接从它的回收池里面拿就行。public void recycle ()：Give back a previously retrieved array, for later re-use重要绘制代码：
super.onDraw(canvas); int centre = getWidth() / 2; // 获取圆心的x坐标 //半径比较 int mixWidth=getMeasuredWidth()>getMeasuredHeight()?getMeasuredHeight():getMeasuredWidth(); mRadius =mRadius>(mixWidth)?(mixWidth):mRadius; mBorderWidth =mRadius/2>=(mBorderWidth)?(mBorderWidth):mRadius/10;//最终的效果要不是自己设置的要不就是半径的1/5 int radius = mRadius/2 - mBorderWidth / 2;// 半径 mLineHeight=Math.abs(getHeight()/2-radius);//这个地方要判断设置正负 if(lineLocation!=-1){ drawLine(canvas,centre); } //绘制背景 bgPaint.setColor(Color.parseColor("#00000000")); bgPaint.setTextSize(mTextSize); canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), bgPaint); //绘制圆 bgPaint.setAntiAlias(true); // 消除锯齿 bgPaint.setColor(mBgColor); bgPaint.setStyle(Paint.Style.FILL); // 设置实心 canvas.drawCircle(centre, centre, radius, bgPaint); //绘制圆环 borderPaint.setStrokeWidth(mBorderWidth); // 设置圆环的宽度 borderPaint.setAntiAlias(true); // 消除锯齿 if (mBorderColor != 0) { borderPaint.setColor(mBorderColor); } else { borderPaint.setColor(borderColor); } borderPaint.setStyle(Paint.Style.STROKE); // 设置实心 canvas.drawCircle(centre,centre, radius - mBorderWidth / 2+mLineWidth/2, borderPaint); //绘制文本 bgPaint.setColor(mTextColor); textPaint.getTextBounds(mTextTitle, 0, mTextTitle.length(), textRect); canvas.drawText(mTextTitle, centre -textRect.width()/2, centre + textRect.height() / 2, bgPaint);这里给了一个int值来判断当前需要绘制那个位置的line；值是0只需绘制 上方line，值是 1只需绘制下方line，值是2同事绘制上下方line,值是-1不需绘制line;这个值由用户使用的时候传递过来这样就可以绘制对应的line
//0 上方 1 下方 2 上下两个 private void drawLine(Canvas canvas, float centre) { linePaint.setColor(borderColor); linePaint.setStrokeWidth(mLineWidth); if (lineLocation == 0) {// canvas.drawLine(centre, 0.5F*centre-mLineHeight, centre, centre, linePaint); canvas.drawLine(centre, 0, centre, mLineHeight*2, linePaint); } else if (lineLocation == 1) { canvas.drawLine(centre, centre, centre, centre * 2F + mLineHeight, linePaint); } else if (lineLocation == 2) {// canvas.drawLine(centre, mRadius * 0.5F - mLineHeight-mBorderWidth, centre, mLineHeight, linePaint); canvas.drawLine(centre, 0, centre, mLineHeight*2, linePaint); canvas.drawLine(centre, centre, centre, centre * 2F + mLineHeight, linePaint); } }使用
这里的使用有两种，一种是在xml中直接布局，设置属性，一种是在代码中初始化然后根据提供的set方法来设置相应的属性。
在你布局中使用的时候要加上
xmlns:app=”http://schemas.android.com/apk/res/com.example.circleview”
com.example.circleview：是包名
这样你就可以设置这个控件的属性了
<com.example.circleview.CircleImg android:id="@+id/itemImg" android:layout_width="100dp" android:layout_height="100dp" android:layout_margin="2dp" app:bgColor="#f88" app:borderColor="#138ddd" app:textColor="#fff" app:textSize="12dp" />最终效果：
基本的一个圆就好了，现在来实现开始的时候的效果图，基本就是用listView实现：
布局文件
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:app="http://schemas.android.com/apk/res/com.example.circleview" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_margin="5dp" android:orientation="vertical" tools:context="com.example.circleview.MainActivity" > <ListView android:id="@+id/listView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:divider="#00000000" android:dividerHeight="0dp" > </ListView></LinearLayout>MainActivity.java:
public class MainActivity extends Activity { private List<String> list=new ArrayList<String>(); ListView listView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initData(); listView=(ListView) findViewById(R.id.listView); listView.setAdapter(new TimeLineAdapter(list, this)); } private void initData() { for (int i =11; i >1; i--) {//时间从小到大 list.add("05/"+i); } }}Adapter:
public class TimeLineAdapter extends BaseAdapter { private static final int[] COLOR = new int[] { 0xff33b5e5, 0xffaa66cc, 0xff99cc00, 0xffffbb33, 0xffff4444,0xff009933,0xffff9988, 0xffffddcc,0xff00ffff,0xffffff00 }; private List<String> list; private Context context; private ViewHolder holder; public TimeLineAdapter(List<String> list, Context context) { super(); this.list = list; this.context = context; } @Override public int getCount() { // TODO Auto-generated method stub return list.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return list.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { int type = getItemViewType(position); if(convertView==null){ convertView=View.inflate(context, R.layout.item,null); holder=new ViewHolder(); convertView.setTag(holder); holder.img=(CircleImg) convertView.findViewById(R.id.itemImg); holder.item=(TextView) convertView.findViewById(R.id.itemText); }else{ holder=(ViewHolder) convertView.getTag(); } holder.img.setBgAndBorderColor(COLOR[position%10]); holder.img.invalidate();//记得重绘 holder.img.setLineLocation(type); holder.img.setmTextTitle(list.get(position)); holder.item.setText("哈哈哈哈哈哈哈哈"); return convertView; } @Override public int getItemViewType(int position) { final int size = list.size() - 1; if (size == 0) return ItemType.ATOM; else if (position == 0) return ItemType.FOOTER; else if (position == size) return ItemType.HEADER; else return ItemType.NORMAL; } class ViewHolder{ TextView item; CircleImg img; }}这里绘制上下line的时候是通过getItemViewType（）返回的view id值来判断的，ItemType中有四个变量：
public final static int NORMAL = 2; //表示绘制上下方public final static int HEADER = 0; //表示绘制下方public final static int FOOTER = 1; //表示绘制上方public final static int ATOM = -1; //表示不绘制然后通过holder.img.setLineLocation(type);来设置当前绘制的line。
CIcleVIew.java下：
public class CircleImg extends View { //画笔 private Paint bgPaint, linePaint, borderPaint,textPaint; private Rect bgRect, textRect; //基本属性 private int mTextSize; private int mTextColor; private String mTextTitle; private int lineColr = Color.parseColor("#AAAAAA"); private int borderColor = Color.parseColor("#AAAAAA"); private int bgColor = Color.parseColor("#138DDD"); private int mBorderColor; private int mBorderWidth = 2; private int mLineColor; private int mLineWidth = 2; private int mLineHeight; private int mBgColor; //line绘制 private int lineLocation = -1;//0 上方 1 下方 2 上下两个 private int mRadius = 40; public CircleImg(Context context) { this(context, null); } //设置line的位置 0 上方 1 下方 2 上下两个 public void setLineLocation(int lineLocation) { this.lineLocation = lineLocation; } //设置纯色的整圆形，包括背景 public void setBgAndBooderCOlor(int color) { this.mBorderColor = color; this.mBgColor = color; } public void setmTextTitle(String mTextTitle) { this.mTextTitle = mTextTitle; } public void setmRadius(int mRadius) { this.mRadius = mRadius; } public CircleImg(Context context, AttributeSet attrs) { this(context, attrs, 0); // TODO Auto-generated constructor stub } public CircleImg(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomCicleView, defStyle, 0); int n = a.getIndexCount(); for (int i = 0; i < n; i++) { int attr = a.getIndex(i); switch (attr) { case R.styleable.CustomCicleView_textSize: // 默认设置为16sp，TypeValue也可以把sp转化为px mTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_PX, 14, getResources().getDisplayMetrics())); break; case R.styleable.CustomCicleView_textColor: mTextColor = a.getColor(attr, Color.BLACK); break; case R.styleable.CustomCicleView_textTitle: mTextTitle = a.getString(attr); break; case R.styleable.CustomCicleView_lineWidth: mLineWidth = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_PX, 2, getResources().getDisplayMetrics())); break; case R.styleable.CustomCicleView_lineColor: mLineColor = a.getColor(attr, lineColr); break; case R.styleable.CustomCicleView_mRadius: mRadius=a.getInt(attr,40); break; case R.styleable.CustomCicleView_borderWidth: mBorderWidth = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_PX, 2, getResources().getDisplayMetrics())); break; case R.styleable.CustomCicleView_borderColor: mBorderColor = a.getColor(attr, borderColor); break; case R.styleable.CustomCicleView_bgColor: mBgColor = a.getColor(attr, bgColor); break; } } a.recycle(); bgPaint = new Paint(); borderPaint = new Paint(); linePaint = new Paint(); textPaint = new Paint(); textRect = new Rect(); textPaint.setTextSize(mTextSize); } //暂时不计算 @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int w = getPaddingLeft() + getPaddingRight(); int h = getPaddingTop() + getPaddingBottom(); if (bgPaint != null) { w += mRadius; h += mRadius; } w = Math.max(w, getMeasuredWidth()); h = Math.max(h, getMeasuredHeight()); int widthSize = resolveSizeAndState(w, widthMeasureSpec, 0); int heightSize = resolveSizeAndState(h, heightMeasureSpec, 0); setMeasuredDimension(widthSize, heightSize); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); int centre = getWidth() / 2; // 获取圆心的x坐标 int radius = mRadius - mBorderWidth / 2;// 半径 mLineHeight=getHeight()/2-radius;//这个地方要判断设置正负 if(lineLocation!=-1){ drawLine(canvas,centre); } //绘制背景 bgPaint.setColor(Color.parseColor("#00000000")); bgPaint.setTextSize(mTextSize); canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), bgPaint); //绘制圆 bgPaint.setAntiAlias(true); // 消除锯齿 bgPaint.setColor(mBgColor); bgPaint.setStyle(Paint.Style.FILL); // 设置实心 canvas.drawCircle(centre, centre, radius, bgPaint); //绘制圆环 borderPaint.setStrokeWidth(mBorderWidth); // 设置圆环的宽度 borderPaint.setAntiAlias(true); // 消除锯齿 if (mBorderColor != 0) { borderPaint.setColor(mBorderColor); } else { borderPaint.setColor(borderColor); } borderPaint.setStyle(Paint.Style.STROKE); // 设置实心 canvas.drawCircle(centre,centre, radius - mBorderWidth / 2+mLineWidth/2, borderPaint); //绘制文本 bgPaint.setColor(mTextColor); textPaint.getTextBounds(mTextTitle, 0, mTextTitle.length(), textRect); canvas.drawText(mTextTitle, centre -textRect.width()/2, centre + textRect.height() / 2, bgPaint); } //0 上方 1 下方 2 上下两个 private void drawLine(Canvas canvas, float centre) { linePaint.setColor(borderColor); linePaint.setStrokeWidth(mLineWidth); if (lineLocation == 0) { canvas.drawLine(centre, centre, centre, centre * 2F + mLineHeight, linePaint); } else if (lineLocation == 1) { canvas.drawLine(centre, 0, centre, mLineHeight*2, linePaint); } else if (lineLocation == 2) { canvas.drawLine(centre, 0, centre, mLineHeight*2, linePaint); canvas.drawLine(centre, centre, centre, centre * 2F + mLineHeight, linePaint); } }}styleable.xml:
<?xml version="1.0" encoding="utf-8"?><resources> <attr name="textSize" format="dimension" /> <attr name="textColor" format="color" /> <attr name="textTitle" format="string" /> <attr name="borderColor" format="color" /> <attr name="borderWidth" format="dimension" /> <attr name="lineColor" format="color" /> <attr name="lineWidth" format="dimension" /> <attr name="bgColor" format="color" /> <attr name="mRadius" format="dimension"/> <declare-styleable name="CustomCicleView"> <attr name="textSize" /> <attr name="textColor" /> <attr name="textTitle" /> <attr name="lineColor" /> <attr name="lineWidth" /> <attr name="bgColor" /> <attr name="borderColor" /> <attr name="borderWidth" /> <attr name="mRadius" /> </declare-styleable></resources>Android是什么
Android是一种基于Linux内核的自由及开放源代码的操作系统，主要使用于移动设备，如智能手机和平板电脑，由美国Google公司和开放手机联盟领导及开发。
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