序言
在最近的项目中需要实现行内标签，我原来觉得挺简单的后来,后来试了很多方式发现并没有那么简单。比如想到的几种实现方式和最终的效果如下图，本着辛苦我一个方便千万家的思想，我把我的TagUtil抽取出来了，并上传到GitHub上了。
这里写图片描述
实现思路
1.首先需要一个tag的布局文件
这里写图片描述
2.手动的填充布局文件，生成一个TextView
3.根据这个TextView获取它的截屏，生成一个Bitmap
4.将bitmap设置到需要显示tag的TextView上，这和TextView中显示表情的原理是一样的。
代码如下
package com.trs.nxnews.news.util;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.text.SpannableString;
import android.text.TextUtils;
import android.text.style.ImageSpan;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;
import com.trs.nxnews.R;
import static android.text.Spanned.SPAN_INCLUSIVE_EXCLUSIVE;
/**
* Created by zhuguohui on 2016/12/12.
*/
public class TagUtil {
public static void setTag(String tag, TextView textView) {
if (TextUtils.isEmpty(tag) || "无".equals(tag)) {
return;
}
//填充tag布局
TextView tv_tag = (TextView) LayoutInflater.from(textView.getContext()).inflate(R.layout.view_tag, null, true);
tv_tag.setText(tag);
//获取View的截图，用来当Tag图标
Bitmap drawingCache = convertViewToBitmap(tv_tag);
//将图片设置到TextView中
BitmapDrawable bitmapDrawable = new BitmapDrawable(drawingCache);
bitmapDrawable.setBounds(0, 0, drawingCache.getWidth(), drawingCache.getHeight());
SpannableString spannableString = new SpannableString(tag + textView.getText());
MyIm imageSpan = new MyIm(bitmapDrawable);
spannableString.setSpan(imageSpan, 0, tag.length(), SPAN_INCLUSIVE_EXCLUSIVE);
textView.setText(spannableString);
}
/**
* 获取tag图标
*
* @param view
* @return
*/
public static Bitmap convertViewToBitmap(View view) {
view.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED), View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
view.buildDrawingCache();
Bitmap bitmap = view.getDrawingCache();
return bitmap;
}
/**
* 可以居中对齐的ImageSPan
*/
public static class MyIm extends ImageSpan {
public MyIm(Context arg0, int arg1) {
super(arg0, arg1);
}
public MyIm(Drawable drawable) {
super(drawable);
}
public int getSize(Paint paint, CharSequence text, int start, int end,
Paint.FontMetricsInt fm) {
Drawable d = getDrawable();
Rect rect = d.getBounds();
if (fm != null) {
Paint.FontMetricsInt fmPaint = paint.getFontMetricsInt();
int fontHeight = fmPaint.bottom - fmPaint.top;
int drHeight = rect.bottom - rect.top;
int top = drHeight / 2 - fontHeight / 4;
int bottom = drHeight / 2 + fontHeight / 4;
fm.ascent = -bottom;
fm.top = -bottom;
fm.bottom = top;
fm.descent = top;
}
//15为padding
return rect.right + 15;
}
@Override
public void draw(Canvas canvas, CharSequence text, int start, int end,
float x, int top, int y, int bottom, Paint paint) {
Drawable b = getDrawable();
canvas.save();
int transY = 0;
transY = ((bottom - top) - b.getBounds().bottom) / 2 + top;
canvas.translate(x, transY);
b.draw(canvas);
canvas.restore();
}
}
}
源码
总结
有一些事情并没有想象中那么简单，多积累一点一滴的技术，学会灵活运用技术，这样开发才会越来越简单，与君共勉。
