对于TextView展示html格式代码,最简单的办法就是使用textview.setText(Html.fromHtml(html));,即便其中有img标签,我们依然可以使用ImageGetter,和TagHandler对其中的图片做处理,但用过的都知道,效果不太理想,甚至无法满足产品简单的需求,那么今天博主就来为大家提供一个完美的解决方案!
html代码示例:
效果图:
首先,要介绍一个开源项目,因为本篇博客所提供的方案是基于这个项目并进行扩展的:
https://github.com/NightWhistler/HtmlSpanner
该项目对html格式代码(内部标签和样式)基本提供了所有的转化方案,效果还是蛮不错的,但对于图片的处理仅做了展示,而对大小设置,点击事件等并未给出解决方案,所以本篇博客即是来对其进行扩展完善,满足日常开发需求!
首先,看HtmlSpanner的使用方法(注:HtmlSpanner内部代码实现不做详细分析,有兴趣的可下载项目研究):
textView.setText(htmlSpanner.fromHtml(html));
htmlSpanner.fromHtml(html)返回的是Spannable格式数据,使用非常简单,但是仅对html做了展示处理,
如果有这样的需求:
-
图片需要动态控制大小;
-
图片点击后可以查看大图;
-
如果有多张图片,点击后进入多图浏览界面,且点进去即是当前图片位置;
这就需要我们能做到以下几点:
-
展示图片(设置图片大小)的代码可控;
-
可以监听图片点击事件;
-
点击图片时可以获取点击的图片url及该图片在全部图片中的position;
那么我们先来看HtmlSpanner对img是如何处理的:
找到项目中类:ImageHanler.java
public class ImageHandler extends TagNodeHandler {
@Override
public void handleTagNode(TagNode node, SpannableStringBuilder builder, int start, int end, SpanStack stack) {
String src = node.getAttributeByName("src");
builder.append("\uFFFC");
Bitmap bitmap = loadBitmap(src); if (bitmap != null) {
Drawable drawable = new BitmapDrawable(bitmap);
drawable.setBounds(0, 0, bitmap.getWidth() - 1,
bitmap.getHeight() - 1);
stack.pushSpan( new ImageSpan(drawable), start, builder.length() );
}
} /**
* Loads a Bitmap from the given url.
*
* @param url
* @return a Bitmap, or null if it could not be loaded.
*/
protected Bitmap loadBitmap(String url) { try { return BitmapFactory.decodeStream(new URL(url).openStream());
} catch (IOException io) { return null;
}
}
}
在handleTagNode方法中我们可以获取到图片的url,并得到了bitmap,有了bitmap那么我们就可以根据bitmap获取图片宽高并动态调整大小了;
drawable.setBounds(0, 0, bitmap.getWidth() - 1,bitmap.getHeight() - 1);
传入计算好的宽高即可;
对于img的点击事件,需要用到TextView的一个方法:setMovementMethod()及一个类:LinkMovementMethod;此时的点击事件不再是view.OnclickListener了,而是通过LinkMovementMethod类中的onTouch事件进行判断的:
@Override public boolean onTouchEvent(TextView widget, Spannable buffer,
MotionEvent event) { int action = event.getAction(); if (action == MotionEvent.ACTION_UP ||
action == MotionEvent.ACTION_DOWN) { int x = (int) event.getX(); int y = (int) event.getY();
x -= widget.getTotalPaddingLeft();
y -= widget.getTotalPaddingTop();
x += widget.getScrollX();
y += widget.getScrollY();
Layout layout = widget.getLayout(); int line = layout.getLineForVertical(y); int off = layout.getOffsetForHorizontal(line, x);
ClickableSpan[] link = buffer.getSpans(off, off, ClickableSpan.class); if (link.length != 0) { if (action == MotionEvent.ACTION_UP) {
link[0].onClick(widget);
} else if (action == MotionEvent.ACTION_DOWN) {
Selection.setSelection(buffer,
buffer.getSpanStart(link[0]),
buffer.getSpanEnd(link[0]));
} return true;
} else {
Selection.removeSelection(buffer);
}
} return super.onTouchEvent(widget, buffer, event);
}
我们知道img标签转化后的最终归宿是ImageSpan,因此我们判断buffer.getSpans为ImageSpan时即点击了图片,捕获了点击不算完事,我们需要一个点击事件的回调啊,因此我们需要重写LinkMovementMethod来完成回调(回调方法有多种,我这里用了一个handler):
package net.nightwhistler.htmlspanner;import android.os.Handler;import android.os.Message;import android.text.Layout;import android.text.Selection;import android.text.Spannable;import android.text.method.LinkMovementMethod;import android.text.method.MovementMethod;import android.view.KeyEvent;import android.view.MotionEvent;import android.widget.TextView;public class LinkMovementMethodExt extends LinkMovementMethod {
private static LinkMovementMethod sInstance; private Handler handler = null; private Class spanClass = null; public static MovementMethod getInstance(Handler _handler,Class _spanClass) { if (sInstance == null) {
sInstance = new LinkMovementMethodExt();
((LinkMovementMethodExt)sInstance).handler = _handler;
((LinkMovementMethodExt)sInstance).spanClass = _spanClass;
} return sInstance;
} int x1; int x2; int y1; int y2; @Override
public boolean onTouchEvent(TextView widget, Spannable buffer,
MotionEvent event) { int action = event.getAction(); if (event.getAction() == MotionEvent.ACTION_DOWN){
x1 = (int) event.getX();
y1 = (int) event.getY();
} if (event.getAction() == MotionEvent.ACTION_UP) {
x2 = (int) event.getX();
y2 = (int) event.getY(); if (Math.abs(x1 - x2) < 10 && Math.abs(y1 - y2) < 10) {
x2 -= widget.getTotalPaddingLeft();
y2 -= widget.getTotalPaddingTop();
x2 += widget.getScrollX();
y2 += widget.getScrollY();
Layout layout = widget.getLayout(); int line = layout.getLineForVertical(y2); int off = layout.getOffsetForHorizontal(line, x2);
Object[] spans = buffer.getSpans(off, off, spanClass); if (spans.length != 0) { if (spans[0] instanceof MyImageSpan){
Selection.setSelection(buffer,
buffer.getSpanStart(spans[0]),
buffer.getSpanEnd(spans[0]));
Message message = handler.obtainMessage();
message.obj = spans[0];
message.what = 2;
message.sendToTarget();
} return true;
}
}
} //return false;
return super.onTouchEvent(widget, buffer, event);
} public boolean canSelectArbitrarily() { return true;
} public boolean onKeyUp(TextView widget, Spannable buffer, int keyCode,
KeyEvent event) { return false;
}
}
注意里面的这部分代码:
if (spans[0] instanceof MyImageSpan)
MyImageSpan是什么鬼?重写的ImageSpan吗?对了就是重写的ImageSpan!为什么要重写呢?我们在通过handler发送ImageSpan并接收到后我们需要通过ImageSpan获取img的url,但此时通过ImageSpan的gerSource()并不能获取到,所以我们就要重写一下ImageSpan,在创建ImageSpan时就把url set进去:
/**
* Created by byl on 2016-12-9.
*/public class MyImageSpan extends ImageSpan{
public MyImageSpan(Context context, Bitmap b) { super(context, b);
} public MyImageSpan(Context context, Bitmap b, int verticalAlignment) { super(context, b, verticalAlignment);
} public MyImageSpan(Drawable d) { super(d);
} public MyImageSpan(Drawable d, int verticalAlignment) { super(d, verticalAlignment);
} public MyImageSpan(Drawable d, String source) { super(d, source);
} public MyImageSpan(Drawable d, String source, int verticalAlignment) { super(d, source, verticalAlignment);
} public MyImageSpan(Context context, Uri uri) { super(context, uri);
} public MyImageSpan(Context context, Uri uri, int verticalAlignment) { super(context, uri, verticalAlignment);
} public MyImageSpan(Context context, @DrawableRes int resourceId) { super(context, resourceId);
} public MyImageSpan(Context context, @DrawableRes int resourceId, int verticalAlignment) { super(context, resourceId, verticalAlignment);
} private String url; public String getUrl() { return url;
} public void setUrl(String url) { this.url = url;
}
同时在ImageHandler类的handleTagNode方法中也要替换ImageSpan:
MyImageSpan span=new MyImageSpan(drawable);
span.setUrl(src);
stack.pushSpan( span, start, builder.length() );
最终的实现流程为:
new Thread(new Runnable() { @Override
public void run() { final Spannable spannable = htmlSpanner.fromHtml(html);
runOnUiThread(new Runnable() { @Override
public void run() {
tv.setText(spannable);
tv.setMovementMethod(LinkMovementMethodExt.getInstance(handler, ImageSpan.class));
}
});
}
}).start();
final Handler handler = new Handler() { public void handleMessage(Message msg) { switch (msg.what) { case 1://获取图片路径列表
String url = (String) msg.obj;
Log.e("jj", "url>>" + url);
imglist.add(url); break; case 2://图片点击事件
int position=0;
MyImageSpan span = (MyImageSpan) msg.obj; for (int i = 0; i < imglist.size(); i++) { if (span.getUrl().equals(imglist.get(i))) {
position = i; break;
}
}
Log.e("jj","position>>"+position);
Intent intent=new Intent(MainActivity.this,ImgPreviewActivity.class);
Bundle b=new Bundle();
b.putInt("position",position);
b.putStringArrayList("imglist",imglist);
intent.putExtra("b",b);
startActivity(intent); break;
}
}
;
};
好了,现在就差点击图片浏览大图(包括多图浏览)了,上面的handler中,当msg.what为1时传来的即是图片路径,这个是在哪里发送的呢?当然是解析html获取到img标签时啦!在ImageHanlder里:
public class ImageHandler extends TagNodeHandler {
Context context;
Handler handler; int screenWidth ; public ImageHandler() {
} public ImageHandler(Context context,int screenWidth, Handler handler) { this.context=context; this.screenWidth=screenWidth; this.handler=handler;
} @Override
public void handleTagNode(TagNode node, SpannableStringBuilder builder,int start, int end, SpanStack stack) { int height;
String src = node.getAttributeByName("src");
builder.append("\uFFFC");
Bitmap bitmap = loadBitmap(src); if (bitmap != null) {
Drawable drawable = new BitmapDrawable(bitmap); if(screenWidth!=0){
Message message = handler.obtainMessage();
message.obj = src;
message.what = 1;
message.sendToTarget();
height=screenWidth*bitmap.getHeight()/bitmap.getWidth();
drawable.setBounds(0, 0, screenWidth,height);
}else{
drawable.setBounds(0, 0, bitmap.getWidth() - 1,bitmap.getHeight() - 1);
}
MyImageSpan span=new MyImageSpan(drawable);
span.setUrl(src);
stack.pushSpan( span, start, builder.length() );
}
} /**
* Loads a Bitmap from the given url.
*
* @param url
* @return a Bitmap, or null if it could not be loaded.
*/
protected Bitmap loadBitmap(String url) { try { return BitmapFactory.decodeStream(new URL(url).openStream());
} catch (IOException io) { return null;
}
}
}
screenWidth变量 和Handler对象都是这在初始化ImageHanlder时传入的,初始化ImageHanlder的地方在HtmlSpanner类的registerBuiltInHandlers()方法中:
if(context!=null){
registerHandler("img", new ImageHandler(context,screenWidth,handler));
}else{
registerHandler("img", new ImageHandler());
}
因此,在ImageHanlder中获取到img的url时就通过handler将其路径发送到主界面存储起来,点击的时候通过比较url得到该图片的position,并和图片列表imglist传入浏览界面即可!
需要注意的是,如果html代码中有图片则需要网络权限,并且加载时需要在线程中…
demo下载地址:http://download.csdn.net/detail/baiyuliang2013/9706568