Textview加入Intent、神情，点击跳转Activity

Textview加入Intent、表情，点击跳转Activity

?? ? ?（第二届 Google 暑期大学生博客分享大赛 - 2011 Android 成长篇）

?? ? ?做过web开发的人应该都知道，在HTML里支持<a>标签在文本里插入一个链接，点击后跳转；并且有<img>标签可以插入图片。Android开发是否也支持呢？带着这个疑问，我们去APIDemos探索一下。OK，在com.example.android.apis.text.link这个类里，官方演示了TextView支持的一些链接，上个图：

?

?? ? ?看来TextView是支持链接跳转的，不过做Android开发的应该都知道，android的View载体是Activity，能不能支持activity跳转呢，很遗憾，不支持。

?? ? ?不过无所谓，Android很有爱，开源的，理解了原理后我们自己去做，这也是我写本篇文章的主要目的，"授之以鱼，不如授之以渔"，希望大家在遇到相似问题时能像我这样去分析源码，然后找出解决办法（或者大家可以提出更好的方法），另外，文中如有不妥的地方，也欢迎大家批评指正。先上效果图：点击左边的链接后跳转到右边。

??

?

?? ?现在我们开始开发吧！第一步，研究相关的源代码吧。通过跟踪TextView的源码，我们发现TextView支持的链接是由android.text.style.URLSpan这个类实现的，它重写了一个onClick方法：

?

public void onClick(View widget) {        Uri uri = Uri.parse(getURL());        Context context = widget.getContext();        Intent intent = new Intent(Intent.ACTION_VIEW, uri);        intent.putExtra(Browser.EXTRA_APPLICATION_ID, context.getPackageName());        context.startActivity(intent);    }

?? ? ?大家看到了吧startActivity，多么熟悉的方法。既然它能实现，为什么我们不能呢，答案是可以的。我们接着跟踪代码，可以看到URLSpan其实继承的是android.text.style.ClickableSpan，我们来看一下他的源码：

?

public abstract class ClickableSpan extends CharacterStyle implements UpdateAppearance {    /**     * Performs the click action associated with this span.     */    public abstract void onClick(View widget);       /**     * Makes the text underlined and in the link color.     */    @Override    public void updateDrawState(TextPaint ds) {        ds.setColor(ds.linkColor);        ds.setUnderlineText(true);    }}

?是不是有点眉目了，我们直接继承这个类，重写他的方法不就可以了吗？大胆假设，小心求证，我们新建一个类：

?

import android.content.Context;import android.content.Intent;import android.text.TextPaint;import android.text.style.ClickableSpan;import android.view.View;/** * If an object of this type is attached to the text of a TextView with a * movement method of LinkMovementMethod, the affected spans of text can be * selected. If clicked, the {@link #onClick} method will be called. *  * @author 张宁 */public class MyClickableSpan extends ClickableSpan {int color = -1;private Context context;private Intent intent;public MyClickableSpan(Context context, Intent intent) {this(-1, context, intent);}/** * constructor * @param color the link color * @param context * @param intent */public MyClickableSpan(int color, Context context, Intent intent) {if (color!=-1) {this.color = color;}this.context = context;this.intent = intent;}/** * Performs the click action associated with this span. */public void onClick(View widget){context.startActivity(intent);};/** * Makes the text without underline. */@Overridepublic void updateDrawState(TextPaint ds) {if (color == -1) {ds.setColor(ds.linkColor);} else {ds.setColor(color);}ds.setUnderlineText(false);}}

?

?? ? ?在这个类里，我们重写了onClick事件，实现了Activity的跳转,并且去掉了下划线。Ok，第一个目的就达到了，下面我们来看一下如何在TextView里加入表情。

?? ? ?这个就比较复杂了，因为TextView只能在其上下左右方向加入图片，是由Drawables这个类实现的，而我们想要的效果是在中间也可以插入，看来这次TextView插入图片源码帮不了我们了。不过我们可以去android.text这个包里去找别的类，大家可以看到在这个包里有一个Html类，做过web开发的应该可以想到什么吧？在文章开头已经提到了Html的<img>标签可以插入图片，那这个类是否提供这个功能呢？带着这个疑问我们可以进去看看，其中有个接口：

?

 /**     * Retrieves images for HTML &lt;img&gt; tags.     */    public static interface ImageGetter {        /**         * This methos is called when the HTML parser encounters an         * &lt;img&gt; tag.  The <code>source</code> argument is the         * string from the "src" attribute; the return value should be         * a Drawable representation of the image or <code>null</code>         * for a generic replacement image.  Make sure you call         * setBounds() on your Drawable if it doesn't already have         * its bounds set.         */        public Drawable getDrawable(String source);    }

?

?? ? 看到<code>source</code>这个没，熟悉吧，结合URLSpan的用法，我们是否可以配合Spanned实现一个

ImageSpan呢？OK，上代码：

?

import java.util.Map;import java.util.Set;import android.content.Context;import android.graphics.drawable.Drawable;import android.text.Html;import android.text.Spanned;import android.text.Html.ImageGetter;/** * this is a class which defining a spanned with image * @author 张宁 * */public class ImageSpan {/** * the map of face. */private Map<String, String> faceMap;private Context context;public ImageSpan(Context context, Map<String, String> faceMap){this.context = context;this.faceMap = faceMap;} /** * get the image by the given key */private ImageGetter imageGetter = new Html.ImageGetter() {@Overridepublic Drawable getDrawable(String source) {Drawable drawable = null;String sourceName = context.getPackageName() + ":drawable/"+ source;int id = context.getResources().getIdentifier(sourceName, null, null);if (id != 0) {drawable = context.getResources().getDrawable(id);if (drawable != null) {drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight());}}return drawable;}};/** * return a {@link Spanned} with image * @param text * @return */public Spanned getImageSpan(CharSequence text){String cs = text.toString();if (faceMap != null) {Set<String> keys = faceMap.keySet();for (String key : keys) {if (cs.contains(key)) {cs = cs.replace(key, "<img src='" + faceMap.get(key) + "'>");}}}return Html.fromHtml(cs, imageGetter, null);}}

?

?? ? ?到目前为止可以说关键代码都已经实现了，但是会有人问，我该如何使用这两个类呢？下面，我们在实现一个工具类来封装这两个类的方法，以方便调用：

?

import java.util.HashMap;import java.util.List;import java.util.Map;import android.content.Context;import android.content.Intent;import android.text.SpannableStringBuilder;import android.text.Spanned;import android.text.TextUtils;import android.text.method.LinkMovementMethod;import android.widget.EditText;import android.widget.TextView;/** * TextView with intent that can redirect to a new activity *  * @author 张宁 *  */public class CustomTextView {private static Map<String, String> faceMap;static {faceMap = new HashMap<String, String>();faceMap.put("[哭]", "face_1");faceMap.put("[怒]", "face_2");}/** * make textview a clickable textview<br> * Note: make true the order of textList and intentList are mapped *  * @param context * @param textView * @param textList *            the text should be set to this textview,not null * @param intentList *            the intent map to the text, if the text have no intent mapped *            to, please set a null value.Or it will happen some unknown *            error.<br> *            not null */public static void setClickableTextView(Context context, TextView textView,List<String> textList, List<Intent> intentList) {if (textList == null || intentList == null) {return;}SpannableStringBuilder builder = new SpannableStringBuilder();int end = -1, length = -1;int size = textList.size();Intent intent;for (int i = 0; i < size; i++) {String text = textList.get(i);if (TextUtils.isEmpty(text)) {continue;}builder.append(textList.get(i));if ((intent = intentList.get(i)) != null) {end = builder.length();length = textList.get(i).length();builder.setSpan(getClickableSpan(context, intent),end - length, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);}builder.append(" ");}textView.setText(builder);textView.setFocusable(true);textView.setMovementMethod(LinkMovementMethod.getInstance());}/** *  make textview a clickable textview<br> *  Note: make true the order of textList and intentList are mapped * @param context * @param textView * @param text * @param intent */public static void setClickableTextView(Context context, TextView textView,String text, Intent intent) {SpannableStringBuilder builder = new SpannableStringBuilder(text);builder.setSpan(getClickableSpan(context, intent), 0, text.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);textView.setText(builder);textView.setMovementMethod(LinkMovementMethod.getInstance());}/** * make TextView a View with image at any index   * @param context * @param textView * @param textList */public static void setImgTextView(Context context, TextView textView,List<String> textList) {StringBuilder builder = new StringBuilder();for (int i = 0; i < textList.size(); i++) {builder.append(textList.get(i)).append(" ");}setImgTextView(context, textView, builder.toString());}/** * make TextView a View with image at any index   * @param context * @param textView * @param text */public static void setImgTextView(Context context, TextView textView,String text) {ImageSpan imageSpan = new ImageSpan(context, faceMap);Spanned spanned = imageSpan.getImageSpan(text);textView.setText(spanned);}/** * make EditText a View with image at any index   * @param context * @param EditText * @param text */public static void setImgTextView(Context context, EditText editText,String text) {ImageSpan imageSpan = new ImageSpan(context, faceMap);Spanned spanned = imageSpan.getImageSpan(text);editText.setText(spanned);}/** * return a custom ClickableSpan *  * @param context * @param intent * @return */public static MyClickableSpan getClickableSpan(Context context,Intent intent) {return new MyClickableSpan(context, intent);}/** * make textview a clickable textview with image<br> * Note: make true the order of textList and intentList are mapped *  * @param context *            not null * @param haveImg *            whether this is image in the text,not null * @param textView *            not null * @param textList *            the text should be set to this textview,not null * @param intentList *            the intent map to the text, if the text have no intent mapped *            to, please set a null value.Or it will happen some unknown *            error.<br> *            allow null */public static void setCustomText(Context context, Boolean haveImg,TextView textView, List<String> textList, List<Intent> intentList) {SpannableStringBuilder builder = new SpannableStringBuilder();int end = -1, length = -1;if (intentList != null) {int size = textList.size();Intent intent;for (int i = 0; i < size; i++) {String text = textList.get(i);if (TextUtils.isEmpty(text)) {continue;}builder.append(textList.get(i));if ((intent = intentList.get(i)) != null) {end = builder.length();length = textList.get(i).length();builder.setSpan(getClickableSpan(context, intent), end- length, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);}builder.append(" ");}} else {for (String text : textList) {builder.append(text).append(" ");}}if (haveImg) {ImageSpan imageSpan = new ImageSpan(context, faceMap);Spanned spanned = imageSpan.getImageSpan(builder);textView.setText(spanned);} else {textView.setText(builder);}textView.setMovementMethod(LinkMovementMethod.getInstance());}}

?

?? ?有了这个类，我们就可以方便的实现在TextView中插入Intent和表情了，甚至不用管底层是怎样实现的，也降低了代码的耦合度。但是又回到我写这篇文章的目的：希望大家能得到“渔”而不仅仅是“鱼”。

?? ?Ok，任务完成。源码奉上。

注：原创作品，转载请标明出处：

?

?http://zhangning290.iteye.com/blog/1134286

?

?

1 楼 lenomon 2012-04-07   实现可点击文本。 android TextView 点击链接 无下划线