昨天写了一篇PermissionsDispatcher初探，文章最后说要用java重写processor模块，今天花了半天时间完成，现在把代码放在github上：https://github.com/ileelay/PermissionsDispatcher/tree/2.2.0j，欢迎大家纠正！同时感慨到Kotlin太强大，Java太繁琐；
虽然Kotlin语法很简练，终究还是基于JVM，同时这篇文章不是循序渐进的Kotlin语法讲解，只是为了记录在转PermissionsDispatcher时的粗略见解；
普通class
kotlin是这样子写的
class NoParametersAllowedException(e: ExecutableElement) : RuntimeException("Method '${e.simpleString()}()' must not have any parameters")
为了保持参数一致，我用java是这样写的：
public class NoParametersAllowedException extends RuntimeException {
public static RuntimeException getInstance(ExecutableElement e) {
return new NoParametersAllowedException("Method "+e.getSimpleName().toString()+" must not have any parameters");
}
private NoParametersAllowedException(String s) {
super(s);
}
}
常量的定义
kotlin这样
//Constants.kt
val FILE_COMMENT = "This file was generated by PermissionsDispatcher. Do not modify!"
val GEN_CLASS_SUFFIX = "PermissionsDispatcher"
val GEN_REQUESTCODE_PREFIX = "REQUEST_"
val GEN_PERMISSION_PREFIX = "PERMISSION_"
val GEN_PENDING_PREFIX = "PENDING_"
val GEN_WITHCHECK_SUFFIX = "WithCheck"
val GEN_PERMISSIONREQUEST_SUFFIX = "PermissionRequest"
说实话，kotlin这样写好变态，连class关键字都不用声明，我用java也尽量保持简洁，可还是比不过它；
public interface Constants {
String FILE_COMMENT = "This file was generated by PermissionsDispatcher. Do not modify!";
String GEN_CLASS_SUFFIX = "PermissionsDispatcher";
String GEN_REQUESTCODE_PREFIX = "REQUEST_";
String GEN_PERMISSION_PREFIX = "PERMISSION_";
String GEN_PENDING_PREFIX = "PENDING_";
String GEN_WITHCHECK_SUFFIX = "WithCheck";
String GEN_PERMISSIONREQUEST_SUFFIX = "PermissionRequest";
}
Extensions
//Extensions.kt
fun TypeMirror.simpleString(): String {
val toString: String = this.toString()
val indexOfDot: Int = toString.lastIndexOf('.')
return if (indexOfDot == -1) toString else toString.substring(indexOfDot + 1)
}
//调用
typeMirror.simpleString()
这个用java写就比较尴尬了，我是用工具类，功能可以实现，但还是没法保持统一的调用方式；
//Extensions.java
public static String TypeMirrorSimpleString(TypeMirror typeMirror) {
String toString = typeMirror.toString();
int indexOfDot = toString.lastIndexOf('.');
if (indexOfDot == -1)
return toString;
else
return toString.substring(indexOfDot + 1);
}
//调用
Extensions.TypeMirrorSimpleString(typeMirror);
初始化一个List
processorUnits = listOf(ActivityProcessorUnit(),SupportFragmentProcessorUnit(),NativeFragmentProcessorUnit())
用java咋写，尴尬了
processorUnits = new ArrayList<ProcessorUnit>();
processorUnits.add(new ActivityProcessorUnit());
processorUnits.add(new SupportFragmentProcessorUnit());
processorUnits.add(new NativeFragmentProcessorUnit());
Safe Call (?. ?:)
先看这一段懵逼的代码
//ADD_WITH_CHECK_BODY_MAP是一个HashMap
ADD_WITH_CHECK_BODY_MAP[needsPermissionParameter]?.addHasSelfPermissionsCondition(builder, activityVar, permissionField) ?: builder.beginControlFlow("if (\$T.hasSelfPermissions(\$N, \$N))", PERMISSION_UTILS, activityVar, permissionField)
用Java理解是啥样子
SensitivePermissionInterface anInterface = ADD_WITH_CHECK_BODY_MAP.get(needsPermissionParameter);
if (anInterface != null) {
anInterface.addHasSelfPermissionsCondition(builder, activityVar, permissionField);
} else {
builder.beginControlFlow("if ($T.hasSelfPermissions($N, $N))", PERMISSION_UTILS, activityVar, permissionField);
}
