Android TextView显示网络图片

来源：互联网发布：网络销售只要做些什么编辑：程序博客网时间：2024/05/17 08:18

前言：程序猿真的是有个通病啊，电梯上就在研究电梯的逻辑代码，走路看到红绿灯也会去研究算法，今天心情不错，于是就发了一个说说，发现某q空间中显示了我发的说说，但是我发的笑脸跟哭脸表情由于网络慢，很久才加载出来，于是我惊讶了，原来表情发的时候存在本地，等发完显示确实网络上拿的，而且还支持gif，好吧，不得不说某q真是牛逼！！

网上textView显示网络图片的例子一大堆啊，但是都不靠谱，于是我弄出了一个靠谱点的思路。

简单介绍下思路吧：
主要就是利用text.setText(Html.fromHtml(“html”));把后台返回的html显示在textview中，后台返回的html可能是这样的：

 String html="dfdfdf<img src=\"http://j1.s2.dpfile.com/pc/5e356bd48d39f4f7f1e37261c29841f5%28700x700%29/thumb.jpg\"/>fdfdfd";

那么如果img中包含的是一个网络的图片链接，我们的源码中有处理吗？？我们接下来看看Html.fromHtml源码：

 @Deprecated    public static Spanned fromHtml(String source, ImageGetter imageGetter, TagHandler tagHandler) {        return fromHtml(source, FROM_HTML_MODE_LEGACY, imageGetter, tagHandler);    }

接着往下看：

  public static Spanned fromHtml(String source, int flags, ImageGetter imageGetter,            TagHandler tagHandler) {      .......省略代码        HtmlToSpannedConverter converter =                new HtmlToSpannedConverter(source, imageGetter, tagHandler, parser, flags);        return converter.convert();    }

然后重点看一下HtmlToSpannedConverter类，在这个类中我们又看到了这么一个方法：

 private void handleStartTag(String tag, Attributes attributes) {        if (tag.equalsIgnoreCase("br")) {            // We don't need to handle this. TagSoup will ensure that there's a </br> for each <br>            // so we can safely emit the linebreaks when we handle the close tag.        } else if (tag.equalsIgnoreCase("p")) {            startBlockElement(mSpannableStringBuilder, attributes, getMarginParagraph());            startCssStyle(mSpannableStringBuilder, attributes);        } else if (tag.equalsIgnoreCase("ul")) {            startBlockElement(mSpannableStringBuilder, attributes, getMarginList());        } else if (tag.equalsIgnoreCase("li")) {            startLi(mSpannableStringBuilder, attributes);        } else if (tag.equalsIgnoreCase("div")) {            startBlockElement(mSpannableStringBuilder, attributes, getMarginDiv());        } else if (tag.equalsIgnoreCase("span")) {            startCssStyle(mSpannableStringBuilder, attributes);        } else if (tag.equalsIgnoreCase("strong")) {            start(mSpannableStringBuilder, new Bold());        } else if (tag.equalsIgnoreCase("b")) {            start(mSpannableStringBuilder, new Bold());        } else if (tag.equalsIgnoreCase("em")) {            start(mSpannableStringBuilder, new Italic());        } else if (tag.equalsIgnoreCase("cite")) {            start(mSpannableStringBuilder, new Italic());        } else if (tag.equalsIgnoreCase("dfn")) {            start(mSpannableStringBuilder, new Italic());        } else if (tag.equalsIgnoreCase("i")) {            start(mSpannableStringBuilder, new Italic());        } else if (tag.equalsIgnoreCase("big")) {            start(mSpannableStringBuilder, new Big());        } else if (tag.equalsIgnoreCase("small")) {            start(mSpannableStringBuilder, new Small());        } else if (tag.equalsIgnoreCase("font")) {            startFont(mSpannableStringBuilder, attributes);        } else if (tag.equalsIgnoreCase("blockquote")) {            startBlockquote(mSpannableStringBuilder, attributes);        } else if (tag.equalsIgnoreCase("tt")) {            start(mSpannableStringBuilder, new Monospace());        } else if (tag.equalsIgnoreCase("a")) {            startA(mSpannableStringBuilder, attributes);        } else if (tag.equalsIgnoreCase("u")) {            start(mSpannableStringBuilder, new Underline());        } else if (tag.equalsIgnoreCase("del")) {            start(mSpannableStringBuilder, new Strikethrough());        } else if (tag.equalsIgnoreCase("s")) {            start(mSpannableStringBuilder, new Strikethrough());        } else if (tag.equalsIgnoreCase("strike")) {            start(mSpannableStringBuilder, new Strikethrough());        } else if (tag.equalsIgnoreCase("sup")) {            start(mSpannableStringBuilder, new Super());        } else if (tag.equalsIgnoreCase("sub")) {            start(mSpannableStringBuilder, new Sub());        } else if (tag.length() == 2 &&                Character.toLowerCase(tag.charAt(0)) == 'h' &&                tag.charAt(1) >= '1' && tag.charAt(1) <= '6') {            startHeading(mSpannableStringBuilder, attributes, tag.charAt(1) - '1');        } else if (tag.equalsIgnoreCase("img")) {            startImg(mSpannableStringBuilder, attributes, mImageGetter);        } else if (mTagHandler != null) {            mTagHandler.handleTag(true, tag, mSpannableStringBuilder, mReader);        }    }

重点看一下这个判断：

else if (tag.equalsIgnoreCase("img")) {            startImg(mSpannableStringBuilder, attributes, mImageGetter);        }

我们看看startImg方法：

  private static void startImg(Editable text, Attributes attributes, Html.ImageGetter img) {        String src = attributes.getValue("", "src");        Drawable d = null;        if (img != null) {            d = img.getDrawable(src);        }        if (d == null) {            d = Resources.getSystem().                    getDrawable(com.android.internal.R.drawable.unknown_image);            d.setBounds(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());        }        int len = text.length();        text.append("\uFFFC");        text.setSpan(new ImageSpan(d, src), len, text.length(),                     Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);    }

看到这里了如果做过TextView的富文本的童鞋有没有一点熟悉了呢？直接创建了一个ImageSpan，然后传入了一个Drawable，那么这个Drawable是哪里来的呢？
是通过 Html.ImageGetter的getDrawable方法获取的！！那么这个mImageGetter对象有没有初始化呢？我们在代码中找找：

是在fromHtml方法中传进去的，也就是说，如果我们不传ImageGetter对象的话，当获取到img标签时，如果ImageGetter为null，那么会走下面判断：

  if (img != null) {            d = img.getDrawable(src);        }        if (d == null) {            d = Resources.getSystem().                    getDrawable(com.android.internal.R.drawable.unknown_image);            d.setBounds(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());        }

而unknown_image就是android系统默认给的一张占位图。

有了前面的了解了，然后我们就开动了，首先得创建一个ImageGetter对象在Html.fromHtml中传给TextView.然后当判断html中有img标签的时候，我们就去网络加载图片，加载完毕后再次赋给TextView.

由于代码简单，我就直接上代码了：

 public TextView text;    private static class MyHandler extends Handler {            private WeakReference<PropertyAnimActivity4_evaluator>activityWeakReference;            public MyHandler(PropertyAnimActivity4_evaluator activity){                activityWeakReference=new WeakReference<PropertyAnimActivity4_evaluator>(activity);            }            @Override            public void handleMessage(Message msg) {                final Drawable drawable= (Drawable) msg.obj;                PropertyAnimActivity4_evaluator activity=activityWeakReference.get();                if(activity!=null){                    String html="dfdfdf<img src=\"http://j1.s2.dpfile.com/pc/5e356bd48d39f4f7f1e37261c29841f5%28700x700%29/thumb.jpg\"/>fdfdfd";                    Spanned spanned = Html.fromHtml(html, new Html.ImageGetter() {                        @Override                        public Drawable getDrawable(String source) {                            return drawable;                        }                    }, null);                    activity.text.setText(spanned);                }            }        }    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_property_anim_activity4_evaluator);        bt_anim_view= (Button) findViewById(R.id.bt_anim_view);        text= (TextView) findViewById(R.id.text);        String html="dfdfdf<img src=\"http://j1.s2.dpfile.com/pc/5e356bd48d39f4f7f1e37261c29841f5%28700x700%29/thumb.jpg\"/>fdfdfd";        Spanned spanned = Html.fromHtml(html, new Html.ImageGetter() {            @Override            public Drawable getDrawable(String source) {                AsyncTask<String, Float, Drawable> task = new AsyncTask<String, Float, Drawable>() {                    @Override                    protected Drawable doInBackground(String... params) {                        try {                            URL url=new URL(params[0]);                            URLConnection con = url.openConnection();                            con.setConnectTimeout(50000);                            Drawable d = Drawable.createFromStream(con.getInputStream(), "");                            d.setBounds(0,0,d.getIntrinsicWidth(),d.getIntrinsicHeight());                            return d;                        } catch (Exception e) {                            e.printStackTrace();                        }                        return null;                    }                    @Override                    protected void onPostExecute(Drawable drawable) {                        Message msg=Message.obtain();                        msg.obj=drawable;                        new MyHandler(PropertyAnimActivity4_evaluator.this).sendMessage(msg);                    }                }.execute(source);                BitmapDrawable bitmapDrawable = new BitmapDrawable(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher));                bitmapDrawable.setBounds(0,0,bitmapDrawable.getIntrinsicWidth(),bitmapDrawable.getIntrinsicHeight());                return bitmapDrawable;            }        }, null);        text.setText(spanned);    }

如果是像某Q一样，放在ListView中，并且显示的是gif图片，又咋搞呢？？？？？小伙伴们如果有好的思路，或者做过类型的，一起探讨一下哈！！！拜谢啦~~~~

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