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。。。

    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>";        }  

    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ArrayList                for(HashMap<String, String> hashMap : datas) {                    //获取key为"type"的值                    String type = hashMap.get("type");                    //如果value=imaeg                    if(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;                }                                @Override                public void run() {                    // TODO Auto-generated method stub                    Drawable 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 exception                        e.printStackTrace();                    }                    //让线程休眠2秒                    SystemClock.sleep(2000);                    //使用Handler更新UI                    Message 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);                }            }                }  

    <?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>  

    <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>