Android中跨包访问Preferences

我们可以在一个应用程序中创建并编辑一个Preferences，然后在另外一个应用程序中读取它。当然有个前提是该<wbr>Preferences</wbr>的权限至少是Context.MODE_WORLD_READABLE。

比如在包名为com.teleca应用程序A中有一个名叫com.teleca_prefer的Preferences：

final static String preferName="com.teleca_prefer";

final static String KEY_TIP="tip";

.......................................................

prefsWorldRead = getSharedPreferences(preferName,

Context.MODE_WORLD_READABLE);

Editor prefsWorldReadEditor = prefsWorldRead.edit();

prefsWorldReadEditor.putString(KEY_TIP, "Are you fine?");

prefsWorldReadEditor.commit();

我们可以在包名为com.teleca.robin应用程序B中这样读取它：

private SharedPreferences prefsWorldRead;

final static String preferName="com.teleca_prefer";

final static String KEY_TIP="tip";

....................................................................

if(prefsWorldRead ==null)

{

Context otherContext=null;

try {

otherContext =createPackageContext("com.teleca",Context.CONTEXT_IGNORE_SECURITY);

} catch (NameNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

prefsWorldRead = otherContext.getSharedPreferences(preferName,

Context.MODE_WORLD_READABLE);

}

String tip=prefsWorldRead.getString(KEY_TIP, "null2");

createPackageContext为Context的方法，"com.teleca"为A应用程序的包名，"com.teleca_prefer"为你要读取的A应用程序的Preferences名字。

public abstractContextcreatePackageContext(StringpackageName, int flags)

Since:API Level 1

Return a new Context object for the given application name. This Context is the same as what the named application gets when it is launched, containing the same resources and class loader. Each call to this method returns a new instance of a Context object; Context objects are not shared, however they share common state (Resources, ClassLoader, etc) so the Context instance itself is fairly lightweight.

ThrowsPackageManager.NameNotFoundExceptionif there is no application with the given package name.

ThrowsSecurityExceptionif the Context requested can not be loaded into the caller's process for security reasons (seeCONTEXT_INCLUDE_CODEfor more information}.

Parameters

packageName flags

Name of the application's package.

Option flags, one ofCONTEXT_INCLUDE_CODEorCONTEXT_IGNORE_SECURITY.

Returns

• A Context for the application.

Throws

PackageManager.NameNotFoundException

java.lang.SecurityException

if there is no application with the given package name