Android - SD Card

在 4.0 後,
Environment.getExternalStorageDirectory().getAbsolutePath();
得到的是內建的儲存空間

因為有些機種可以外接SD卡, 有些不行, 而 Android 沒有提供取得外接SD卡的方法,

MAC - shortcut

fn + "UP" arrow = page up
fn + "Down" arrow = page down
fn + "Right" arrow = move cursor to the end of line
fn + "Left" arrow = move cursor to the start of line

fn + delete = delete word after current cursor position


In windows 7

fn + ctrl + "Left" arrow = Home
fn + ctrl + "Right" arrow = End

ctrl + alt + "UP" arrow = screen turn to  0 angle (restore the default angle)
ctrl + alt + "Down" arrow = screen turn to 180 angle
ctrl + alt + "Left" arrow = screen turn to 270 angle
ctrl + alt + "Right" arrow = screen turn to 90 angle

Ref

http://support.apple.com/kb/HT1343

http://forums.macrumors.com/showthread.php?t=665383

Eclipse - Logcat

什麼是 Logcat ?

(暫無)

設定視窗( in Eclipse)

Window → Preferences → Android → Logcat

打開訊息視窗

Window → Show View → Other → Android → Logcat

Android - Toast 顯示很慢

   Toast可以用來顯示音量改變或者保存更新消息，如果用戶一直點擊，Toast會排隊一個一個的，直到消息隊列全部顯示完，這樣的效果顯然是不好的，下面來看解決方法

    Toast.makeText(activity, text, duration)每次會實例化一個Toast，所以

01 if (toast != null)

02

{

03	toast.setText(text);

04	toast.setDuration(duration);

05	toast.show();

06

} else

07

{

08	toast = Toast.makeText(activity, text, duration);

09	toast.show();

10

}

Android - Change Default Activity

Use the AndroidManifest.xml file, you can actually even have more than one launcher activity specified in your application manifest. To make an activity seen on the launcher you add these attributes to your activity in the manifest

        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>

Ref.

http://stackoverflow.com/questions/3631982/change-applications-starting-activity-android

http://stackoverflow.com/questions/9704898/how-to-set-my-activity-as-main-activity-in-android 

Android - ViewPager的使用, 左右滑動效果

java.lang.Object
↳	android.view.View
	↳	android.view.ViewGroup
		↳	android.support.v4.view.ViewPager

參照 官方 API 
看得出來 ViewPager 不在既定的 android sdk 裡面, 在 3.0 以前要自己
導入 android-support-v4.jar

drawable 裡面檔名限制
有張圖片檔名 04_065.jpg 能放進去, 但是要使用會出錯, R檔案也會有個錯誤符號
後來嘗試更改檔名, eclipse 告訴我
" The resource name must begin with a character. "
所以前面隨便加個英文字就ok


PS.
android-support-v4.jar路徑
android-sdk\extras\android\support\v4
現在直接 download Android SDK 的話大部分都直接附在裡面了

Ref.
[DEVDIV原创] 使用ViewPager实现左右滑动效果
http://www.devdiv.com/forum.php?mod=viewthread&tid=125963&extra=page%3D1%26filter%3Dtypeid%26typeid%3D381%26typeid%3D381

[DEVDIV原创] 使用ViewFlipper实现左右滑动效果

http://www.devdiv.com/forum.php?mod=viewthread&tid=125943&extra=page%3D1%26filter%3Dtypeid%26typeid%3D381%26typeid%3D381

Android - java.lang.OutOfMemoryError 解決方法

01.
檢查一下程式裡頭的迴圈, 是不是太複雜了
02.
重新建立個虛擬 Android , 將 Heap 數值設定大一點





Ref.

[Java] java.lang.OutOfMemoryError 的解決方法
http://www.neo.com.tw/archives/482

完美解决java.lang.OutOfMemoryError: bitmap size exceeds VM budget
http://blog.csdn.net/yangxyjd/article/details/6932989