Android-自定义TextView和异步加载图片的实现
Android-自定义TextView和异步加载图片的实现
实例：ConstomTextView
实现步骤：
1. 定义一个继承LinearLayout的类：ConstomTextView
2. 在ConstomTextView类中自定义setText()方法
3.在setText方法中，通过TypedArray来获取自定义属性，来设置组件相应的参数
4.如果要在布局中显示出图片就应该定义ImageView,显示出文本就定义TextView，以此类推
5. 最后要将组件通过addView（）方法添加到布局当中。
6. 要实现图片异步加载，需要定义一个线程类，通过Handler来进行数据交互，来达到UI的更新
项目运行效果：
2秒过后。。。
源代码：MainActivity.java
package com.wwj.textView;import java.util.ArrayList;import java.util.HashMap;import android.os.Bundle;import android.app.Activity;public class MainActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); /**********************测试数据**********************/ ArrayList<HashMap<String, String>> datas = new ArrayList<HashMap<String,String>>(); HashMap<String, String> hashMap1 = new HashMap<String, String>(); hashMap1.put("type", "image"); hashMap1.put("value", "http://www.taoqao.com/uploads/allimg/111216/1-111216101257.png"); HashMap<String, String> hashMap2 = new HashMap<String, String>(); hashMap2.put("type", "text"); hashMap2.put("value", newsbody); HashMap<String, String> hashMap3 = new HashMap<String, String>(); hashMap3.put("type", "image"); hashMap3.put("value", "http://www.taoqao.com/uploads/allimg/111216/1-111216101257.png"); datas.add(hashMap1); datas.add(hashMap2); datas.add(hashMap3); /*************************************************************************/ //获取自定义组件的引用 ConstomTextView view = (ConstomTextView) findViewById(R.id.textView); //调用ConstomTextView自定义的setText方法 view.setText(datas); } //新闻信息 private final String newsbody = " <p> 今年浙江卫视凭《中国好声音》一举做大" + "，其巨大的影响力直接波及到了各家卫视“跨年晚会”的战略部署。日前" + "，“跨年晚会”概念的鼻祖湖南卫视率先表示“退出跨年烧钱大战”。" + "但据湖南卫视内部人士透露，即使如此，今年的湖南跨年晚会也将会掂出“跨年季”这个概念" + "，“也就是从12月27日到12月31日，连续五天，我们将相继用《百变大咖秀》、《快乐大本营》" + "、《女人如歌》、《天天向上》的特别节目来连续打造这个”季“的概念，直到12月31日的那场晚会。”</p>";}
源代码：ConstomTextView.java
package com.wwj.textView;import java.net.URL;import java.util.ArrayList;import java.util.HashMap;import android.content.Context;import android.content.res.TypedArray;import android.graphics.drawable.Drawable;import android.os.Handler;import android.os.Message;import android.os.SystemClock;import android.text.Html;import android.util.AttributeSet;import android.view.Gravity;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.TextView;public class ConstomTextView extends LinearLayout{//上下文对象private Context mContext;//声明TypedArray的引用private TypedArray mTypedArray;//布局参数private LayoutParams params;public ConstomTextView(Context context) {super(context);}public ConstomTextView(Context context, AttributeSet attrs) {super(context, attrs);this.mContext = context;this.setOrientation(LinearLayout.VERTICAL);//从attrs.xml文件中那个获取自定义属性mTypedArray = context.obtainStyledAttributes(attrs, R.styleable.constomTextView);}public void setText(ArrayList<HashMap<String, String>> datas) {//遍历ArrayListfor(HashMap<String, String> hashMap : datas) {//获取key为"type"的值String type = hashMap.get("type");//如果value=imaegif(type.equals("image")){//获取自定义属性属性int imagewidth = mTypedArray.getDimensionPixelOffset(R.styleable.constomTextView_image_width, 100);int imageheight = mTypedArray.getDimensionPixelOffset(R.styleable.constomTextView_image_height, 100);ImageView imageView = new ImageView(mContext);params = new LayoutParams(imagewidth, imageheight);params.gravity = Gravity.CENTER_HORIZONTAL;//居中imageView.setLayoutParams(params);//显示图片imageView.setImageResource(R.drawable.ic_constom);//将imageView添加到LinearLayout当中addView(imageView);//启动异步线程更新异步显示图片信息new DownloadPicThread(imageView, hashMap.get("value")).start();}else {float textSize = mTypedArray.getDimension(R.styleable.constomTextView_textSize, 16);int textColor = mTypedArray.getColor(R.styleable.constomTextView_textColor, 0xFF0000FF);TextView textView = new TextView(mContext);textView.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));textView.setText(Html.fromHtml(hashMap.get("value")));textView.setTextSize(textSize);//设置字体大小textView.setTextColor(textColor);//设置字体颜色addView(textView);}}}private Handler handler = new Handler() {public void handleMessage(android.os.Message msg) {@SuppressWarnings("unchecked")HashMap<String, Object> hashMap = (HashMap<String, Object>) msg.obj;ImageView imageView = (ImageView) hashMap.get("imageView");LayoutParams params = new LayoutParams(msg.arg1, msg.arg2);params.gravity = Gravity.CENTER_HORIZONTAL;//居中imageView.setLayoutParams(params);Drawable drawable = (Drawable) hashMap.get("drawable");imageView.setImageDrawable(drawable);//显示图片};};/** * 定义一个线程类，异步加载图片 * @author Administrator * */private class DownloadPicThread extends Thread {private ImageView imageView;private String mUrl;public DownloadPicThread(ImageView imageView, String mUrl) {super();this.imageView = imageView;this.mUrl = mUrl;}@Overridepublic void run() {// TODO Auto-generated method stubDrawable drawable = null;int newImgWidth = 0;int newImgHeight = 0;try {drawable = Drawable.createFromStream(new URL(mUrl).openStream(), "image");//对图片进行缩放newImgWidth = drawable.getIntrinsicWidth() / 3;newImgHeight = drawable.getIntrinsicHeight() / 3;} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}//让线程休眠2秒SystemClock.sleep(2000);//使用Handler更新UIMessage msg = handler.obtainMessage();HashMap<String, Object> hashMap = new HashMap<String, Object>();hashMap.put("imageView", imageView);hashMap.put("drawable", drawable);msg.obj = hashMap;msg.arg1 = newImgWidth;msg.arg2 = newImgHeight;handler.sendMessage(msg);}}}
自定义属性：/values/attrs.xml
<?xml version="1.0" encoding="utf-8"?><resources> <declare-styleable name="constomTextView"> <attr name="image_width" format="dimension"/> <attr name="image_height" format="dimension"/> <attr name="textColor" format="color"/> <attr name="textSize" format="dimension"/> </declare-styleable></resources>
布局文件：main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:wwj="http://schemas.android.com/apk/res/com.wwj.textView" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/LinearLayout1" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <com.wwj.textView.ConstomTextView android:id="@+id/textView" android:layout_width="fill_parent" android:layout_height="wrap_content" wwj:image_width="200dip" wwj:image_height="52dip"/></LinearLayout>