Android code segment 7 (3)

Preface

Finally, I collected another article. This series focuses on practicality. Welcome to share with me and recommend useful code segments ~~

 

Statement
You are welcome to repost, but please keep the original source of the article :)
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Body

1. Obtain the path of the installed APK

PackageManager pm = getPackageManager ();

For (ApplicationInfo app: pm. getInstalledApplications (0 )){
Log. d ("PackageList", "package:" + app. packageName + ", sourceDir:" + app. sourceDir );
}

The output is as follows:

Package: com. tmobile. thememanager, sourceDir:/system/app/themanager.apk
Package: com. touchtype. swiftkey, sourceDir:/data/apps/com.touchtype.swiftkey-1.apk

Reprinted from here.

 

2. multi-process Preferences data sharing

Public static void putStringProcess (Context ctx, String key, String value ){
SharedPreferences sharedPreferences = ctx. getSharedPreferences ("preference_mu", Context. MODE_MULTI_PROCESS );
Editor editor = sharedPreferences. edit ();
Editor. putString (key, value );
Editor. commit ();
}

Public static String getStringProcess (Context ctx, String key, String defValue ){
SharedPreferences sharedPreferences = ctx. getSharedPreferences ("preference_mu", Context. MODE_MULTI_PROCESS );
Return sharedPreferences. getString (key, defValue );
}

Related Articles:

Http://zengrong.net/post/1687.htm

 

Iii. Conversion from generic ArrayList to array

@ SuppressWarnings ("unchecked ")
Public static <T> T [] toArray (Class <?> Cls, ArrayList <T> items ){
If (items = null | items. size () = 0 ){
Return (T []) Array. newInstance (cls, 0 );
}
Return items. toArray (T []) Array. newInstance (cls, items. size ()));
}

 

Iv. Save and restore the current position of ListView

Private void saveCurrentPosition (){
If (mListView! = Null ){
Int position = mListView. getFirstVisiblePosition ();
View v = mListView. getChildAt (0 );
Int top = (v = null )? 0: v. getTop ();
// Save position and top
}
}

Private void restorePosition (){
If (mFolder! = Null & mListView! = Null ){
Int position = 0; // retrieves the stored data
Int top = 0; // retrieves the stored data
MListView. setSelectionFromTop (position, top );
}
}

It can be stored in Preference or in a database, and set after data is loaded.

 

5. Call portable hotspot and data sharing settings

Public static Intent getHotspotSetting (){
Intent intent = new Intent ();
Intent. setAction (Intent. ACTION_MAIN );
ComponentName com = new ComponentName ("com. android. settings", "com. android. settings. TetherSettings ");
Intent. setComponent (com );
Return intent;
}

 

6. format the output IP Address

Public static String getIp (Context ctx ){
Return Formatter. formatIpAddress (WifiManager) ctx. getSystemService (Context. WIFI_SERVICE). getConnectionInfo (). getIpAddress ());
}

 

7. Sort folders (sort folders first and sort files later)

 

Public static void sortFiles (File [] files ){
Arrays. sort (files, new Comparator <File> (){

@ Override
Public int compare (File lhs, File rhs ){
// Return a negative number indicating that o1 is less than o2, return 0 indicating that o1 is equal to o2, and return a positive number indicating that o1 is greater than o2.
Boolean l1 = lhs. isDirectory ();
Boolean l2 = rhs. isDirectory ();
If (l1 &&! L2)
Return-1;
Else if (! L1 & l2)
Return 1;
Else {
Return lhs. getName (). compareTo (rhs. getName ());
}
}
});
}

 

 

Series 

Android code segment 7 (II)

Android code segment 7 (1)