传送门 ☞ 轮子的专栏 ☞ 转载请注明 ☞ http://blog.csdn.net/leverage_1229
今天我们学习如何自定义TextView组件，让它既能显示文本，又能显示图像，达到“图文并茂”的效果。这种图文混搭的方式常常被用来展现新闻、文章、彩信等内容。下面给出该情景的案例：
1案例技术要点
1.1创建attrs.xml文件用于设置自定义组件的属性、类型和样式。
1.2利用android.content.res.TypedArray类将自定义组件装载到程序，以供程序调用。
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.customTextView);
1.3布局文件引入自定义组件需要如下设置
自定义组件命名空间：
xmlns:custom="http://schemas.android.com/apk/res/com.custom.textview"
自定义组件标签：
<com.custom.textview.CustomTextView .../>
1.4构造一个HashMap数据结构，用于保存自定义组件的内容类型和值。
key：自定义组件的内容类型（image、text）
value：自定义组件的内容值（imageUrl，CharSequence）
1.5利用android.widget.LinearLayout.LayoutParams类用于设置组件的布局参数。这里需要根据显示内容的类型动态地设置组件的布局参数。
2案例代码陈列
2.1工程包目录
2.2AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.custom.textview"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name">
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
2.3strings.xml
<resources>
<string name="app_name">自定义TextView实现图文并茂</string>
</resources>
2.4自定义TextView组件的属性类型样式文件：attrs.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="customTextView">
<attr name="image_width" format="dimension" />
<attr name="image_height" format="dimension" />
<attr name="text_color" format="color" />
<attr name="text_size" format="dimension" />
</declare-styleable>
</resources>
2.5main.xml
<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:custom="http://schemas.android.com/apk/res/com.custom.textview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@android:color/white" >
<com.custom.textview.CustomTextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
custom:image_width="200dp"
custom:image_height="50dp" />
</LinearLayout>
2.6自定义组件类：CustomTextView.java
package com.custom.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 CustomTextView extends LinearLayout {
private Context context;
private TypedArray typedArray;
private LayoutParams params;
public CustomTextView(Context context) {
super(context);
}
public CustomTextView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
this.setOrientation(LinearLayout.VERTICAL);
// 从attrs.xml中获取自定义属性
typedArray = context.obtainStyledAttributes(attrs, R.styleable.customTextView);
}
public void setText(ArrayList<HashMap<String, String>> data) {
for (HashMap<String, String> hashMap : data) {
String type = hashMap.get("type");
String value = hashMap.get("value");
// 如果内容类型是图片
if (type.equals("image")) {
// 设置图片显示宽高、集中
int imageWidth = typedArray.getDimensionPixelOffset(R.styleable.customTextView_image_width, 100);
int imageHeight = typedArray.getDimensionPixelOffset(R.styleable.customTextView_image_height, 100);
ImageView imageView = new ImageView(context);
params = new LayoutParams(imageWidth, imageHeight);
params.gravity = Gravity.CENTER_HORIZONTAL;
imageView.setLayoutParams(params);
// 显示默认图片
imageView.setImageResource(R.drawable.ic_launcher);
// 将ImageView添加到CustomTextView中
addView(imageView);
// 开启工作线程异步加载图片
new DownloadWork(value, imageView).start();
} else if (type.equals("text")) {
int textColor = typedArray.getColor(R.styleable.customTextView_text_color, 0xFF0000FF);
float textSize = typedArray.getDimension(R.styleable.customTextView_text_size, 16);
TextView textView = new TextView(context);
textView.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
textView.setText(Html.fromHtml(value));
textView.setTextColor(textColor);
textView.setTextSize(textSize);
addView(textView);
}
}
}
private class DownloadWork extends Thread {
private String imageUrl;
private ImageView imageView;
public DownloadWork(String imageUrl, ImageView imageView) {
this.imageUrl = imageUrl;
this.imageView = imageView;
}
@Override
public void run() {
URL url = null;
Drawable drawable = null;
int newImageWidth = 0;
int newImageHeight = 0;
try {
url = new URL(imageUrl);
drawable = Drawable.createFromStream(url.openStream(), "image");
// 对图片进行缩放
newImageWidth = drawable.getIntrinsicWidth() / 3;
newImageHeight = drawable.getIntrinsicHeight() / 3;
} catch (Exception e) {
e.printStackTrace();
}
SystemClock.sleep(2000);
HashMap<String, Object> map = new HashMap<String, Object>();
map.put("imageView", imageView);
map.put("drawable", drawable);
Message msg = handler.obtainMessage();
msg.obj = map;
msg.arg1 = newImageWidth;
msg.arg2 = newImageHeight;
handler.sendMessage(msg);
}
}
private Handler handler = new Handler() {
public void handleMessage(Message msg) {
@SuppressWarnings("unchecked")
HashMap<String, Object> map = (HashMap<String, Object>) msg.obj;
ImageView imageView = (ImageView) map.get("imageView");
LayoutParams params = new LayoutParams(msg.arg1, msg.arg2);
params.gravity = Gravity.CENTER_HORIZONTAL;
imageView.setLayoutParams(params);
Drawable drawable = (Drawable) map.get("drawable");
imageView.setImageDrawable(drawable);
}
};
}
2.7MainActivity.java
package com.custom.textview;
import java.util.ArrayList;
import java.util.HashMap;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {
private final String text = " <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>";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 采集显示内容数据
ArrayList<HashMap<String, String>> data = new ArrayList<HashMap<String,String>>();
HashMap<String, String> part1 = new HashMap<String, String>();
part1.put("type", "image");
part1.put("value", "http://www.linuxidc.com/upload/2012_12/121218101020341.png");
HashMap<String, String> part2 = new HashMap<String, String>();
part2.put("type", "text");
part2.put("value", text);
HashMap<String, String> part3 = new HashMap<String, String>();
part3.put("type", "image");
part3.put("value", "http://www.linuxidc.com/upload/2012_12/121218101020341.png");
data.add(part1);
data.add(part2);
data.add(part3);
CustomTextView customTextView = (CustomTextView) findViewById(R.id.textView);
customTextView.setText(data);
}
}
3案例效果展示
