diff options
Diffstat (limited to 'tools/layoutlib/create/README.txt')
| -rw-r--r-- | tools/layoutlib/create/README.txt | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/tools/layoutlib/create/README.txt b/tools/layoutlib/create/README.txt index 65a64cd..894611b 100644 --- a/tools/layoutlib/create/README.txt +++ b/tools/layoutlib/create/README.txt @@ -30,9 +30,9 @@ The Android JAR can't be used directly in Eclipse: Consequently this tool: - parses the input JAR, - modifies some of the classes directly using some bytecode manipulation, -- filters some packages and removes some that we don't want to end in the output JAR, +- filters some packages and removes those we don't want in the output JAR, - injects some new classes, -- and generates a modified JAR file that is suitable for the Android plugin +- generates a modified JAR file that is suitable for the Android plugin for Eclipse to perform rendering. The ASM library is used to do the bytecode modification using its visitor pattern API. @@ -63,7 +63,7 @@ with their dependencies and then only keep the ones we want. To do that, the analyzer is created with a list of base classes to keep -- everything that derives from these is kept. Currently the one such class is android.view.View: -since we want to render layouts, anything that is sort of the view needs to be kept. +since we want to render layouts, anything that is sort of a view needs to be kept. The analyzer is also given a list of class names to keep in the output. This is done using shell-like glob patterns that filter on the fully-qualified @@ -90,6 +90,7 @@ and lists: - the classes to inject in the output JAR -- these classes are directly implemented in layoutlib_create and will be used to interface with the renderer in Eclipse. - specific methods to override (see method stubs details below). +- specific methods for which to delegate calls. - specific methods to remove based on their return type. - specific classes to rename. @@ -114,6 +115,9 @@ Methods are also changed from protected/private to public. The code of the methods is then kept as-is, except for native methods which are replaced by a stub. Methods that are to be overridden are also replaced by a stub. +The transformed class is then fed through the DelegateClassAdapter to implement +method delegates. + Finally fields are also visited and changed from protected/private to public. @@ -131,8 +135,7 @@ method being called, its caller object and a flag indicating whether the method was native. We do not currently provide the parameters. The listener can however specify the return value of the overridden method. -An extension being worked on is to actually replace these listeners by -direct calls to a delegate class, complete with parameters. +This strategy is now obsolete and replaced by the method delegates. - Strategies @@ -160,6 +163,9 @@ methods to override. Instead it removes the original code and replaces it by a call to a specific OveriddeMethod.invokeX(). The bridge then registers a listener on the method signature and can provide an implementation. +This strategy is now obsolete and replaced by the method delegates. +See strategy 5 below. + 3- Renaming classes @@ -195,6 +201,24 @@ example, the inner class Paint$Style in the Paint class should be discarded and bridge will provide its own implementation. +5- Method Delegates + +This strategy is used to override method implementations. +Given a method SomeClass.MethodName(), 1 or 2 methods are generated: +a- A copy of the original method named SomeClass.MethodName_Original(). + The content is the original method as-is from the reader. + This step is omitted if the method is native, since it has no Java implementation. +b- A brand new implementation of SomeClass.MethodName() which calls to a + non-existing static method named SomeClass_Delegate.MethodName(). + The implementation of this 'delegate' method is done in layoutlib_brigde. + +The delegate method is a static method. +If the original method is non-static, the delegate method receives the original 'this' +as its first argument. If the original method is an inner non-static method, it also +receives the inner 'this' as the second argument. + + + - References - -------------- |