Android eclipse : Error generating final archive: Debug certificate expired on

how to fix it?

Answer:

Delete your debug certificate under ~/.android/debug.keystore; the directory is something like %USERHOME%/.androidon Windows.

Unfortunately a debug certificate is only valid for 365 days. To generate a new one you must delete the existing debug.keystore file. Its location is platform dependent - you can find it in Preferences - Android - Build - Default debug keystore.

The Eclipse plugin should then generate a new certificate when you next try to build a debug package. You may need to clean and then build to generate the certificate.

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android cross activity variable scope

xxClass appState = ((xxClass)getApplicationContext());

appState.variable_in_another_activity

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Eclipse Hot Key

Shift-Alt-Arrow Up :

to mark the surrounding block to the current block (and Shift-Alt-Arrow Down to narrow down again).

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AutoCompleteTextView has white text color when setting Theme_Light solution!

AutoCompleteTextView 在 Theme_Light 時 字體白色,背景也白色導致看不到.

solution!

1. use an extended theme in your manifest:
...
<application android:theme="@style/Theme.Light.NoTitleBar.mytheme" ... >
...

2. create the new theme (res/values/themes.xml) which uses fixed styles:
...
<style name="Theme.Light.NoTitleBar.mytheme" parent="@android:style/Theme.Light.NoTitleBar">
<item name="android:autoCompleteTextViewStyle">@style/AutoCompleteTextViewLight</item>
<item name="android:dropDownItemStyle">@style/Widget.DropDownItemLight</item>
</style>
...

3. create the styles (res/values/styles.xml) which fix the color:
...
<style name="AutoCompleteTextViewLight" parent="@android:style/Widget.AutoCompleteTextView">
<item name="android:textColor">@android:color/primary_text_light</item>
</style>
<style name="Widget.DropDownItemLight" parent="@android:style/Widget.DropDownItem">
<item name="android:textColor">@android:color/primary_text_light</item>
</style>
...

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Android Hide the title bar in 2 ways

Android 隱藏標題列 狀態列

隱藏標題列
In android programming, we can hide the title bar in 2 ways.
Hiding the title bar is used to show the full screen in browser,game related applications, etc.

First method is through AndroidManifest.xml.
Use below source in your androidmanifest.xml to hide the title bar.

<activity android:name=".your class Name"
android:theme="@android:style/Theme.NoTitleBar"
</activity>

Second method is through coding
//before setContentView
requestWindowFeature(Window.FEATURE_NO_TITLE);


隱藏status bar。
//hide system status bar
final Window win = getWindow();
win.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);

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Android go to url 中文亂碼解決方法

android 中，利用瀏覽器來開啟網頁的做法為

String url_Str = "http://www.google.com.tw";

Uri uri = Uri.parse(url_Str);
Intent intent = new Intent(Intent.ACTION_VIEW,uri);
startActivity(intent);

以上程式即可以開啟網頁，但是若要在url後面加上參數則可能會造成中文亂碼問頭發生,解決方法為將參數利用URLEncoder.encode轉成utf8再傳送即可


String url_Str="http://www.yahoo.com/search?test="+URLEncoder.encode("字串","UTF-8");

Uri uri = Uri.parse(url_Str);
Intent intent = new Intent(Intent.ACTION_VIEW,uri);
startActivity(intent);

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Android programming keep screen on

You may seen numerous methods describing how to keep the screen on, they using the PowerManager.WakeLock API. But access WakeLock too often will drain the battery, here is an easy approach let Android do it for you.

Just add android:keepScreenOn="true " to your app layout .

Example:

...........

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:keepScreenOn="true">

.........

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