http://www.devdiv.net/bbs/thread-33989-1-1.html
1、Video
对于视频，取第一帧作为缩略图，也就是怎样从filePath得到一个Bitmap对象。
private Bitmap createVideoThumbnail(String filePath) {
Bitmap bitmap = null;
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
try {
retriever.setMode(MediaMetadataRetriever.MODE_CAPTURE_FRAME_ONLY);
retriever.setDataSource(filePath);
bitmap = retriever.captureFrame();
} catch(IllegalArgumentException ex) {
// Assume this is a corrupt video file
} catch (RuntimeException ex) {
// Assume this is a corrupt video file.
} finally {
try {
retriever.release();
} catch (RuntimeException ex) {
// Ignore failures while cleaning up.
}
}
return bitmap;
}
Android提供了MediaMetadataRetriever，由JNI(media_jni)实现。
看得出MediaMetadataRetriever主要有两个功能：MODE_GET_METADATA_ONLY和MODE_CAPTURE_FRAME_ONLY
这里设mode为MODE_CAPTURE_FRAME_ONLY，调用captureFrame取得一帧。
另外还有两个方法可以用：
extractMetadata 提取文件信息，ARTIST、DATE、YEAR、DURATION、RATING、FRAME_RATE、VIDEO_FORMAT
和extractAlbumArt 提取专辑信息，这个下面的音乐文件可以用到。
2、Music
对于音乐，取得AlbumImage作为缩略图，还是用MediaMetadataRetriever
private Bitmap createAlbumThumbnail(String filePath) {
Bitmap bitmap = null;
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
try {
retriever.setMode(MediaMetadataRetriever.MODE_GET_METADATA_ONLY);
retriever.setDataSource(filePath);
byte[] art = retriever.extractAlbumArt();
bitmap = BitmapFactory.decodeByteArray(art, 0, art.length);
} catch(IllegalArgumentException ex) {
} catch (RuntimeException ex) {
} finally {
try {
retriever.release();
} catch (RuntimeException ex) {
// Ignore failures while cleaning up.
}
}
return bitmap;
}
retriever.extractAlbumArt()得到的是byte数组，还需要一步用BitmapFactory编码得到Bitmap对象。
3、Image
图片就很简单了
Bitmap bm = null;
Options op = new Options();
op.inSampleSize = inSampleSize;
op.inJustDecodeBounds = false;
bm = BitmapFactory.decodeFile(mFile.getPath(), op);
能直接得到Bitmap对象，把图片缩小到合适大小就OK。
同样上面的Video和Music，retrive到Bitmap后也需要缩小处理。
很多网站都通过User-Agent来判断浏览器类型，如果是3G手机，显示手机页面内容，如果是普通浏览器，显示普通网页内容。）User Agent （以下简称 UA）是一个浏览器的身份标识，比如我正在用的 Chromium UA 就是
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10
各个参数的含义如下表：
Chrome 8.0.552.224 Mozilla MozillaProductToken. Claims to be a Mozilla based user agent, which is only true for Gecko browsers like Firefox and Netscape. For all other user agents it means 'Mozilla-compatible'. In modern browsers, this is only used for historical reasons. It has no real meaning anymore 5.0 Mozilla Version Windows Platform U Security values:
- N for no security
- U for strong security
- I for weak security
Windows 7 en-US Language Tag, indicates the language for which the client had been localized (e.g. menus and buttons in the user interface)
en-US = English - United States AppleWebKit The Web Kit provides a set of core classes to display web content in windows 534.10 Web Kit build KHTML KHTML like Gecko like Gecko Chrome Name :
Chrome 8.0.552.224 Version Safari Based on Safari 534.10 Safari build Description: Free open-source web browser developed by Google. Chromium is the name of the open source project behind Google Chrome, released under the BSD license.
All Chrome user agent strings
谷歌Chrome浏览器，可以很方便地用来当3G手机模拟器。在Windows的【开始】-->【运行】中输入以下命令，启动谷歌浏览器，即可模拟相应手机的浏览器去访问3G手机网页：
谷歌Android：
苹果iPhone：
或
chrome.exe --user-agent="Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_0 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A341 Safari/528.16"
诺基亚N97：
试一试，分别用Android、iPhone、诺基亚访问http://g.iuni.com.cn、http://www.163.com/、http://blog.s135.com/、http://www.google.com.hk/、http://3g.qq.com、http://t.sina.cn这些3G手机网页，看看有什么不同。
更多款手机的User-Agent：http://www.zytrax.com/tech/web/mobile_ids.html
如果想切换回普通浏览器模式，关掉所有Chrome浏览器，重开即可。如果不想关闭浏览器，切回普通浏览器模式，则访问：
1)FrameLayout常常与 merge 相关，关于他们各自的介绍，请参阅相关的文档。在这里，
用来合并两个透明的png图片，就像photoshop里图层合并一样。
2)Frame动画animation-list，常常用于制作短片动画或用于进程进度的一个指示标识。
先附图如下:
下面是部分代码:
res/anim/scrolling.xml
<?xml version="1.0" encoding="utf-8"?> <animation-list xmlns:android="http://schemas.android.com/apk/res/android" id="selected" android:oneshot="false"> <item android:drawable="@drawable/ball1" android:duration="80" /> <item android:drawable="@drawable/ball2" android:duration="80" /> <item android:drawable="@drawable/ball3" android:duration="80" /> <item android:drawable="@drawable/ball4" android:duration="80" /> <item android:drawable="@drawable/ball5" android:duration="80" /> <item android:drawable="@drawable/ball6" android:duration="80" /> </animation-list>
res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_centerHorizontal="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/frame01">
<ImageView android:src="/blog_article/@drawable/line/index.html"
android:layout_width="300sp"
android:layout_height="200sp">
</ImageView>
<ImageView android:src="/blog_article/@drawable/bar/index.html"
android:layout_width="300sp"
android:layout_height="200sp">
</ImageView>
</FrameLayout>
<ImageView android:id="@+id/scrolling_anim"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_centerHorizontal="true"
android:layout_below="@id/frame01"
android:layout_marginTop="15sp"/>
</RelativeLayout>package com.sunflower;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.widget.ImageView;
public class FrameActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
ImageView img = (ImageView)findViewById(R.id.scrolling_anim);
img.setBackgroundResource(R.anim.scrolling); //设置动画的载体(画布)
StopAnim mar2 = new StopAnim();
Timer t2 = new Timer(false);
t2.schedule(mar2, 10000); //10秒后停止动画
}
class StartUpAnim extends TimerTask {
public void run() {
ImageView img = (ImageView)findViewById(R.id.scrolling_anim);
// Get the background, which has been compiled to an AnimationDrawable object.
AnimationDrawable frameAnimation = (AnimationDrawable) img.getBackground();
// Start the animation (looped playback by default).
frameAnimation.start();
}
}
class StopAnim extends TimerTask {
public void run()
{
ImageView img = (ImageView)findViewById(R.id.scrolling_anim);
// Get the background, which has been compiled to an AnimationDrawable object.
AnimationDrawable frameAnimation = (AnimationDrawable) img.getBackground();
// stop the animation (looped playback by default).
frameAnimation.stop();
}
}
@Override
protected void onResume() {
super.onResume();
StartUpAnim mar = new StartUpAnim(); //放在这里执行是让frameAnimation有足够的时间取得画布(Images's background)
Timer t = new Timer(false);
t.schedule(mar, 1000); //延迟1秒后才开始动画
}
}附件是整个app project.