下面会详细的介绍实现的过程。
1.构想思路
其实在拿到设计的一个效果，我们首先要做的就是去思考，怎么实现，就算不好实现，也要实现一个折中的两边都可以妥协的方案。
由于当前是要展示10天以上的天气的情况，那么如果采用一个view绘制的形式肯定会影响到性能，那其实很快就想到了ListView，这不就是一个横向的ListView的效果么，考虑到ListView并没有横向的效果，转而就想到了RecyclerView，RecyclerView的LinearLayoutManager可以直接设置为横向的，这解决了使用什么来实现的问题。
1.1最高温度和最低温度在View上面怎么绘制
这个问题不是太难，可以这样，拿到这15天的最低温度和最高温度，这个需要我们计算，从这15个最高以及最低温度里面找到最大以及最小的，然后使用这两个温度差去映射View的高度，最后可以得到需要的绘制的圆点View的Y轴的计算公式:
需要在View上面绘制的高度=(今天的温度−15天里面最低温度)View的高度15天里面最高温度−15天里面最低温度
1.2折线在每个view的最左边个最右边的位置
这个也很简单，用
昨天的温度+今天的温度2
然后再经过上面的计算就可以得到需要绘制的Y轴的位置。
2.具体实现
2.1WeatherLineView的实现
自定义WeatherLineView，需要下面的几个属性:
<declare-styleable name="WeatherLineView"> <!-- 文字大小 --> <attr name="temperTextSize" format="dimension"/> <!-- 文字的颜色 --> <attr name="weatextColor" format="color"/> <!-- 绘制的线的宽度 --> <attr name="weaLineWidth" format="dimension"/> <!-- 绘制的圆点的半径 --> <attr name="weadotRadius" format="dimension"/> <!-- 文字离圆点的距离 --> <attr name="textDotDistance" format="dimension"/> </declare-styleable>
具体的实现:
public class WeatherLineView extends View {
/**
* 默认最小宽度50dp
*/
private static final int defaultMinWidth = 100; /**
* 默认最小高度80dp
*/
private static final int defaultMinHeight = 80; /**
* 字体最小默认16dp
*/
private int mTemperTextSize = 16; /**
* 文字颜色
*/
private int mWeaTextColor = Color.BLACK; /**
* 线的宽度
*/
private int mWeaLineWidth = 1; /**
* 圆点的宽度
*/
private int mWeaDotRadius = 5; /**
* 文字和点的间距
*/
private int mTextDotDistance = 5; /**
* 画文字的画笔
*/
private TextPaint mTextPaint; /**
* 文字的FontMetrics
*/
private Paint.FontMetrics mTextFontMetrics; /**
* 画点的画笔
*/
private Paint mDotPaint; /**
* 画线的画笔
*/
private Paint mLinePaint; /**
* 15天最低温度的数据
*/
private int mLowestTemperData; /**
* 15天最高温度的数据
*/
private int mHighestTemperData; /**
* 分别代表最左边的，中间的，右边的三个当天最低温度值
*/
private int mLowTemperData[]; private int mHighTemperData[]; public WeatherLineView(Context context) { this(context, null);
} public WeatherLineView(Context context, AttributeSet attrs) { this(context, attrs, 0);
} public WeatherLineView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr);
init(context, attrs, defStyleAttr);
initPaint();
} /**
* 设置当天的三个低温度数据，中间的数据就是当天的最低温度数据，
* 第一个数据是当天和前天的数据加起来的平均数，
* 第二个数据是当天和明天的数据加起来的平均数
*
* @param low 最低温度
* @param high 最高温度
*/
public void setLowHighData(int low[], int high[]) {
mLowTemperData = low;
mHighTemperData = high;
invalidate();
} /**
* 设置15天里面的最低和最高的温度数据
*
* @param low 最低温度
* @param high 最高温度
*/
public void setLowHighestData(int low, int high) {
mLowestTemperData = low;
mHighestTemperData = high;
invalidate();
} /**
* 设置画笔信息
*/
private void initPaint() {
mTextPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG);
mTextPaint.setTextSize(mTemperTextSize);
mTextPaint.setColor(mWeaTextColor);
mTextFontMetrics = mTextPaint.getFontMetrics();
mDotPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mDotPaint.setStyle(Paint.Style.FILL);
mDotPaint.setColor(mWeaTextColor);
mLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mLinePaint.setStyle(Paint.Style.STROKE);
mLinePaint.setStrokeWidth(mWeaLineWidth);
mLinePaint.setColor(mWeaTextColor);
} /**
* 获取自定义属性并赋初始值
*/
private void init(Context context, AttributeSet attrs, int defStyleAttr) {
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.WeatherLineView,
defStyleAttr, 0);
mTemperTextSize = (int) a.getDimension(R.styleable.WeatherLineView_temperTextSize,
dp2px(context, mTemperTextSize));
mWeaTextColor = a.getColor(R.styleable.WeatherLineView_weatextColor, Color.parseColor("#b07b5c"));
mWeaLineWidth = (int) a.getDimension(R.styleable.WeatherLineView_weaLineWidth,
dp2px(context, mWeaLineWidth));
mWeaDotRadius = (int) a.getDimension(R.styleable.WeatherLineView_weadotRadius,
dp2px(context, mWeaDotRadius));
mTextDotDistance = (int) a.getDimension(R.styleable.WeatherLineView_textDotDistance,
dp2px(context, mTextDotDistance));
a.recycle();
} @Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int width = getSize(widthMode, widthSize, 0); int height = getSize(heightMode, heightSize, 1);
setMeasuredDimension(width, height);
} /**
* @param mode Mode
* @param size Size
* @param type 0表示宽度，1表示高度
* @return 宽度或者高度
*/
private int getSize(int mode, int size, int type) { // 默认
int result; if (mode == MeasureSpec.EXACTLY) {
result = size;
} else { if (type == 0) { // 最小不能低于最小的宽度
result = dp2px(getContext(), defaultMinWidth) + getPaddingLeft() + getPaddingRight();
} else { // 最小不能小于最小的宽度加上一些数据
int textHeight = (int) (mTextFontMetrics.bottom - mTextFontMetrics.top); // 加上2个文字的高度
result = dp2px(getContext(), defaultMinHeight) + 2 * textHeight + // 需要加上两个文字和圆点的间距
getPaddingTop() + getPaddingBottom() + 2 * mTextDotDistance;
} if (mode == MeasureSpec.AT_MOST) {
result = Math.min(result, size);
}
} return result;
} @Override
protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (mLowTemperData == null || mHighTemperData == null
|| mLowestTemperData == 0 || mHighestTemperData == 0) { return;
}
canvas.drawColor(Color.YELLOW); // 文本的高度
int textHeight = (int) (mTextFontMetrics.bottom - mTextFontMetrics.top); // 一个基本的高度，由于最下面的时候，有文字和圆点和文字的宽度需要留空间
int baseHeight = getHeight() - textHeight - mTextDotDistance; // 最低温度相关
// 最低温度中间
int calowMiddle = baseHeight - cacHeight(mLowTemperData[1]);
canvas.drawCircle(getWidth() / 2, calowMiddle, mWeaDotRadius, mDotPaint); // 画温度文字
String text = String.valueOf(mLowTemperData[1]) + "°"; int baseX = (int) (canvas.getWidth() / 2 - mTextPaint.measureText(text) / 2); // mTextFontMetrics.top为负的
// 需要加上文字高度和文字与圆点之间的空隙
int baseY = (int) (calowMiddle - mTextFontMetrics.top) + mTextDotDistance;
canvas.drawText(text, baseX, baseY, mTextPaint); if (mLowTemperData[0] != 0) { // 最低温度左边
int calowLeft = baseHeight - cacHeight(mLowTemperData[0]);
canvas.drawLine(0, calowLeft, getWidth() / 2, calowMiddle, mLinePaint);
} if (mLowTemperData[2] != 0) { // 最低温度右边
int calowRight = baseHeight - cacHeight(mLowTemperData[2]);
canvas.drawLine(getWidth() / 2, calowMiddle, getWidth(), calowRight, mLinePaint);
} // 最高温度相关
// 最高温度中间
int calHighMiddle = baseHeight - cacHeight(mHighTemperData[1]);
canvas.drawCircle(getWidth() / 2, calHighMiddle, mWeaDotRadius, mDotPaint); // 画温度文字
String text2 = String.valueOf(mHighTemperData[1]) + "°"; int baseX2 = (int) (canvas.getWidth() / 2 - mTextPaint.measureText(text2) / 2); int baseY2 = (int) (calHighMiddle - mTextFontMetrics.bottom) - mTextDotDistance;
canvas.drawText(text2, baseX2, baseY2, mTextPaint); if (mHighTemperData[0] != 0) { // 最高温度左边
int calHighLeft = baseHeight - cacHeight(mHighTemperData[0]);
canvas.drawLine(0, calHighLeft, getWidth() / 2, calHighMiddle, mLinePaint);
} if (mHighTemperData[2] != 0) { // 最高温度右边
int calHighRight = baseHeight - cacHeight(mHighTemperData[2]);
canvas.drawLine(getWidth() / 2, calHighMiddle, getWidth(), calHighRight, mLinePaint);
}
} private int cacHeight(int tem) { // 最低，最高温度之差
int temDistance = mHighestTemperData - mLowestTemperData; int textHeight = (int) (mTextFontMetrics.bottom - mTextFontMetrics.top); // view的最高和最低之差，需要减去文字高度和文字与圆点之间的空隙
int viewDistance = getHeight() - 2 * textHeight - 2 * mTextDotDistance; // 今天的温度和最低温度之间的差别
int currTemDistance = tem - mLowestTemperData; return currTemDistance * viewDistance / temDistance;
} public static int dp2px(Context context, float dpVal) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
dpVal, context.getResources().getDisplayMetrics());
}
}上面就是折线的天气View，代码的注释比较详细了。
2.2RecyclerView的Item的布局
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal"> <View android:layout_width="0.5dp" android:layout_height="match_parent" android:background="#A04D4E"/> <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="vertical"> <View android:layout_width="match_parent" android:layout_height="1dp" android:background="#A04D4E"/> <TextView android:id="@+id/id_day_text_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="10dp" android:text="多云" android:textSize="18sp"/> <ImageView android:id="@+id/id_day_icon_iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="10dp" android:src="@drawable/wth_code_99"/> <yong.qing.com.qimingview.weatherview.WeatherLineView android:id="@+id/wea_line" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <ImageView android:id="@+id/id_night_icon_iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:src="@drawable/wth_code_99"/> <TextView android:id="@+id/id_night_text_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginBottom="10dp" android:layout_marginTop="10dp" android:text="多云" android:textSize="18sp"/> <View android:layout_width="match_parent" android:layout_height="1dp" android:background="#A04D4E"/> </LinearLayout> <View android:layout_width="0.5dp" android:layout_height="match_parent" android:background="#A04D4E"/></LinearLayout>
当然这里那些属性我没有加上去，因为代码里面有设置默认值，如果觉得不满足要求的话，可以自己设置。
2.3RecyclerView的adapter的实现
public class WeaDataAdapter extends RecyclerView.Adapter<WeaDataAdapter.WeatherDataViewHolder> {
private Context mContext;
private LayoutInflater mInflater;
private List<WeatherDailyModel> mDatas;
private int mLowestTem;
private int mHighestTem;
public WeaDataAdapter(Context context, List<WeatherDailyModel> datats, int lowtem, int hightem) {
mContext = context;
mInflater = LayoutInflater.from(context);
mDatas = datats;
mLowestTem = lowtem;
mHighestTem = hightem;
}
@Override
public WeatherDataViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.item_weather_item, parent, false);
WeatherDataViewHolder viewHolder = new WeatherDataViewHolder(view);
viewHolder.dayText = (TextView) view.findViewById(R.id.id_day_text_tv);
viewHolder.dayIcon = (ImageView) view.findViewById(R.id.id_day_icon_iv);
viewHolder.weatherLineView = (WeatherLineView) view.findViewById(R.id.wea_line);
viewHolder.nighticon = (ImageView) view.findViewById(R.id.id_night_icon_iv);
viewHolder.nightText = (TextView) view.findViewById(R.id.id_night_text_tv);
return viewHolder;
}
@Override
public void onBindViewHolder(WeatherDataViewHolder holder, int position) {
// 最低温度设置为15，最高温度设置为30
Resources resources = mContext.getResources();
WeatherDailyModel weatherModel = mDatas.get(position);
holder.dayText.setText(weatherModel.getText_day());
int iconday = resources.getIdentifier("wth_code_" + weatherModel.getCode_day(), "drawable", mContext.getPackageName());
if (iconday == 0) {
holder.dayIcon.setImageResource(R.drawable.wth_code_99);
} else {
holder.dayIcon.setImageResource(iconday);
}
holder.weatherLineView.setLowHighestData(mLowestTem, mHighestTem);
int iconight = resources.getIdentifier("wth_code_" + weatherModel.getCode_day(), "drawable", mContext.getPackageName());
if (iconight == 0) {
holder.nighticon.setImageResource(R.drawable.wth_code_99);
} else {
holder.nighticon.setImageResource(iconight);
}
holder.nightText.setText(weatherModel.getText_night());
int low[] = new int[3];
int high[] = new int[3];
low[1] = weatherModel.getLow();
high[1] = weatherModel.getHigh();
if (position <= 0) {
low[0] = 0;
high[0] = 0;
} else {
WeatherDailyModel weatherModelLeft = mDatas.get(position - 1);
low[0] = (weatherModelLeft.getLow() + weatherModel.getLow()) / 2;
high[0] = (weatherModelLeft.getHigh() + weatherModel.getHigh()) / 2;
}
if (position >= mDatas.size() - 1) {
low[2] = 0;
high[2] = 0;
} else {
WeatherDailyModel weatherModelRight = mDatas.get(position + 1);
low[2] = (weatherModel.getLow() + weatherModelRight.getLow()) / 2;
high[2] = (weatherModel.getHigh() + weatherModelRight.getHigh()) / 2;
}
holder.weatherLineView.setLowHighData(low, high);
}
@Override
public int getItemCount() {
return mDatas.size();
}
public static class WeatherDataViewHolder extends RecyclerView.ViewHolder {
TextView dayText;
ImageView dayIcon;
WeatherLineView weatherLineView;
ImageView nighticon;
TextView nightText;
public WeatherDataViewHolder(View itemView) {
super(itemView);
}
}
}Model里面的字段:
public static class WeatherDailyModel {
/**
* date : 2016-05-30
* text_day : 多云
* code_day : 4
* text_night : 阴
* code_night : 9
* high : 34
* low : 22
*/
private String date; private String text_day; private int code_day; private String text_night; private int code_night; private int high; private int low;
}2.4Activity里面获取数组设置到RecyclerView里面去
private void initView() { //得到控件
mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview_horizontal); //设置布局管理器
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
mRecyclerView.setLayoutManager(layoutManager);
} private void fillDatatoRecyclerView(List<WeatherDailyModel> daily) {
mWeatherModels = daily;
Collections.sort(daily, new Comparator<WeatherDailyModel>() {
@Override public int compare(WeatherDailyModel lhs,
WeatherDailyModel rhs) { // 排序找到温度最低的，按照最低温度升序排列
return lhs.getLow() - rhs.getLow();
}
}); int low = daily.get(0).getLow();
Collections.sort(daily, new Comparator<WeatherDailyModel>() {
@Override public int compare(WeatherDailyModel lhs,
WeatherDailyModel rhs) { // 排序找到温度最高的，按照最高温度降序排列
return rhs.getHigh() - lhs.getHigh();
}
}); int high = daily.get(0).getHigh();
mWeaDataAdapter = new WeaDataAdapter(this, mWeatherModels, low, high);
mRecyclerView.setAdapter(mWeaDataAdapter);
}这样其实就搞定了，WeatherLineView可能比较麻烦一点吧，但是只要是想清楚了，就很好了，从上面也看到WeatherLineView没什么含金量的，就是很普通的绘制。
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