paulwu0115: Android

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2014年1月27日星期一

Developing for Android in Eclipse: R.java not generating

Solution

Make sure that anything the R. links to is not broken. Fix all errors in your XML files. If anything in the ADKs are broken, R will not regenerate.
If you somehow hit something and created import android.R in your activity, remove it.
Run Project -> Clean. This will delete and regenerate R and BuildConfig.
Make sure Project -> Build Automatically is ticked. If not, build it manually via Menu -> Project -> Build Project .
Wait a few seconds for the errors to disappear.
If it doesn't work, delete everything inside the /gen/ folder
If it still doesn't work, try right-clicking your project -> Android Tools -> Fix Project Properties.
Check your *.properties files (in the root folder of your app folder) and make sure that the links in there are not broken.
Right-click your project > properties > Android. Look at the Project Build Target and Library sections on the right side of the page. Your Build Target should match the target in your AndroidManifest.xml. So if it's set to target 17 in AndroidManifest, make sure that the Target Name is Android 4.2. If your Library has an X under the reference, remove and re-add the library until there's a green tick. This might happen if you've moved a few files and folders around.
What to do if R doesn't regenerate

This usually happens when you have a broken xml file.

Check errors inside your XML files, mainly within the /res/ folder
Common places are /layout/ and /values/ especially if you've changed one of them recently
Check AndroidManifest.xml, I find that often I change a string, and forget to change the string name from AndroidManifest.xml.
Check that Android SDK Build-tools is installed. Window->Android SDK Manager->Tools->Android SDK Build-tools
Make sure when you update the Android SDK Tools, you also update the Android SDK Platform-tools and Android ASK Build-tools. Build fails silently if they don't match.
If you can't find the issue, right click /gen/ -> Restore from local history... -> tick R.java -> click Restore. This doesn't solve the problem, but it will clear out the extra errors to make the problem easier to find.
I know there's already a lot of answers here, but this is the main link on Google, so I'm compiling all the advice here and hope it helps someone else new to this :)

android自带的base64编码

首先导入包
import android.util.Base64;
String 变量=android.util.Base64.encodeToString(字符串.getBytes(),Base64.DEFAULT);
也可简写为
String 变量=Base64.encodeToString(字符串.getBytes(),Base64.DEFAULT);
至于解码
byte b[]=android.util.Base64.decode(字符串,Base64.DEFAULT);
String 变量=new String(b);
byte b[]=android.util.Base64.decode(字符串,Base64.DEFAULT);

Export有關android手機的Database

有關android手機的Database (expoortDB.db) 目前可以Export 出來,
方法如下

1 open dos command

2 切換到 android sdk path

ex: d:
cd D:\adt-bundle-windows\sdk

3 輸入 adb shell (確認Phone Device 是連線中狀能)
ex: adb shell

4 輸入 run-as package-name
ex: run-as tw.com.test
(ps 在AndriodManifest.xml 找的到pakcage name)

5 輸入 ls 有看到Databases 目錄

6 輸入 cd databases

7 輸入cat expoortDB.db > /sdcard/expoortDB.db

8 再到手機的APPs-> 我的檔案
找到expoortDB.db 用分享經由 ( Gmail or 雲端硬碟) 把檔案滙出

9 由7~8 把想要的檔案滙出

再用SQLite Database Browser 軟体(free) 即可以看內容的Table 結構及資料

2014年1月20日星期一

[Android]使用DDMS匯出sqlite資料庫

在Android中可以使用Eclipse外掛程式DDMS來查看，也可以使用Android工具包中的adb工具來查看。android專案中的sqlite資料庫位於/data/data/專案包/databases中。

使用DDMS匯出sqlite資料庫。

1、首先打開android專案的調試模式，然後找到顯示DDMS：

選擇DDMS

2、切換到DDMS，顯示File Explorer視窗，找到/data/data/

然後找到套裝程式的資料夾，打開databases，就能看到sqlite資料庫檔了。選擇將其匯出。

這樣就把sqlite資料庫檔以檔的方式匯出來了，然後使用sqlite介面管理工具如sqlite administrator、sqlite man或者firefox外掛程式sqlite manager等打開就可以了。

使用adb工具訪問sqlite資料庫

Android Debug Bridge（ADB）是Android的一個通用調試工具，它可以更新設備或模擬器中的代碼，可以管理預定埠，可以在設備上運行shell命令，我們知道android是基於Linux內核，它的內部檔結構也是採用linux檔組織方式，因此訪問它的檔結構需要使用shell。這次我們就會用shell來訪問android應用中的sqlite資料庫檔。

1、運行cmd，切換到android-sdk目錄，運行adb.exe，加上參數shell，出現#號就代表進入了shell命令模式，注意adb要在Android模擬器運行時才能進入shell：