記一次寫Intent的擴充套件
摘要：
寫專案的時候經常會寫到跳轉Activiey，寫到跳轉Activit就一定會寫到putExtra，就像下面那樣
intent.putExtra("a", item.a)
intent.putExtra("b", item.b)
intent.putExtr...
寫專案的時候經常會寫到跳轉Activiey，寫到跳轉Activit就一定會寫到putExtra，就像下面那樣
intent.putExtra("a", item.a)
intent.putExtra("b", item.b)
intent.putExtra("c", item.c)
挺多哈，每次都要重複前面相同的內容，所以就想著能不能寫個擴充套件來簡寫。
開始
我們最終實現是這樣的：
Intent(context, TestActivity::class.java) .putExtraVararg( "a" to item.a, "b" to item.b, "c" to item.c )
仿mapOf
經常用到mapOf()
或者mutableMapOf()
就會知道，裡面是用了Pair
類來生成Map的，所以受此啟發，打算用Pair
來作為引數實現，那麼寫的時候就應該是這樣寫，引數為可變引數型別：
// 作為Intent的擴充套件
fun Intent.putExtraVararg(
vararg extras: Pair<String, Any?>
): Intent {
// 先省略
}
putExtra
的第一個引數型別肯定是String
型別，第二個引數的型別包括Bundle, Boolean, BooleanArray, Byte, ByteArray, Char, CharArray, String
等等，所以就用Any
型別，因為是可空的，所以加上?
。
那麼呼叫的時候，就是這樣子的
Intent(context, TestActivity::class.java) .putExtraVararg( "a" to item.a, "b" to item.b, "c" to item.c )
是不是就是一開始說的那樣，對比平常寫的是不是簡單了很多。
引數型別匹配
寫好了引數，那麼就要進行對引數型別的匹配進行對應的putExtra
。
vararg
引數可以用forEach
來迴圈對每個引數型別進行匹配：
fun Intent.putExtraVararg(
vararg extras: Pair<String, Any?>
): Intent {
if (extras.isEmpty()) return this
extras.forEach { (key, value) ->
value ?: let {
it.putExtra(key, it.toString())
return@forEach
}
when (value) {
is Bundle -> this.putExtra(key, value)
is Boolean -> this.putExtra(key, value)
is BooleanArray -> this.putExtra(key, value)
is Byte -> this.putExtra(key, value)
is ByteArray -> this.putExtra(key, value)
is Char -> this.putExtra(key, value)
is CharArray -> this.putExtra(key, value)
is String -> this.putExtra(key, value)
is CharSequence -> this.putExtra(key, value)
is Double -> this.putExtra(key, value)
is DoubleArray -> this.putExtra(key, value)
is Float -> this.putExtra(key, value)
is FloatArray -> this.putExtra(key, value)
is Int -> this.putExtra(key, value)
is IntArray -> this.putExtra(key, value)
is Long -> this.putExtra(key, value)
is LongArray -> this.putExtra(key, value)
is Short -> this.putExtra(key, value)
is ShortArray -> this.putExtra(key, value)
is Parcelable -> this.putExtra(key, value)
is Serializable -> this.putExtra(key, value)
else -> {
throw IllegalArgumentException("Not support$valuetype${value.javaClass}..")
}
}
}
return this
}
發現沒有，還少了ArrayList<String>
、ArrayList<CharSequence>
、ArrayList<? extends Parcelable>
這三個List的引數型別匹配，因為不能直接is
來匹配對應的Array型別，在群裡問過之後，才得出最終的方法，Array裡面有一個匹配對應型別的擴充套件函式isArrayOf()
：
/**
* Checks if array can contain element of type [T].
*/
@Suppress("REIFIED_TYPE_PARAMETER_NO_INLINE")
public fun <reified T : Any>Array<*>.isArrayOf(): Boolean =
T::class.java.isAssignableFrom(this::class.java.componentType)
so，這樣就簡單了，我們先匹配Array
，然後在匹配對應的ArrayList<String>
、ArrayList<CharSequence>
、ArrayList<? extends Parcelable>
，最後在對應put方法那裡用as
：
is Array<*> -> {
@Suppress("UNCHECKED_CAST")
when {
value.isArrayOf<String>() -> {
this.putStringArrayListExtra(key, value as ArrayList<String?>)
}
value.isArrayOf<CharSequence>() -> {
this.putCharSequenceArrayListExtra(key, value as ArrayList<CharSequence?>)
}
value.isArrayOf<Parcelable>() -> {
this.putParcelableArrayListExtra(key, value as ArrayList<out Parcelable?>)
}
}
}
這樣就實現了不同Array
型別的putExtra
。
最終
最後完整的程式碼為
fun Intent.putExtraVararg(
vararg extras: Pair<String, Any?>
): Intent {
if (extras.isEmpty()) return this
extras.forEach {
val key = it.first
val value = it.second ?: let {
it.putExtra(key, it.toString())
}
}
extras.forEach { (key, value) ->
value ?: let {
it.putExtra(key, it.toString())
return@forEach
}
when (value) {
is Bundle -> this.putExtra(key, value)
is Boolean -> this.putExtra(key, value)
is BooleanArray -> this.putExtra(key, value)
is Byte -> this.putExtra(key, value)
is ByteArray -> this.putExtra(key, value)
is Char -> this.putExtra(key, value)
is CharArray -> this.putExtra(key, value)
is String -> this.putExtra(key, value)
is CharSequence -> this.putExtra(key, value)
is Double -> this.putExtra(key, value)
is DoubleArray -> this.putExtra(key, value)
is Float -> this.putExtra(key, value)
is FloatArray -> this.putExtra(key, value)
is Int -> this.putExtra(key, value)
is IntArray -> this.putExtra(key, value)
is Long -> this.putExtra(key, value)
is LongArray -> this.putExtra(key, value)
is Short -> this.putExtra(key, value)
is ShortArray -> this.putExtra(key, value)
is Array<*> -> {
@Suppress("UNCHECKED_CAST")
when {
value.isArrayOf<String>() -> {
this.putStringArrayListExtra(key, value as ArrayList<String?>)
}
value.isArrayOf<CharSequence>() -> {
this.putCharSequenceArrayListExtra(key, value as ArrayList<CharSequence?>)
}
value.isArrayOf<Parcelable>() -> {
this.putParcelableArrayListExtra(key, value as ArrayList<out Parcelable?>)
}
}
}
is Parcelable -> this.putExtra(key, value)
is Serializable -> this.putExtra(key, value)
else -> {
throw IllegalArgumentException("Not support$valuetype${value.javaClass}..")
}
}
}
return this
}
轉成Java是這樣的：
public final class IntentExtKt{
@NotNull
public static final Intent putExtraVararg(@NotNull Intent $receiver, @NotNull Pair... extras){
Intrinsics.checkParameterIsNotNull($receiver, "receiver$0");
Intrinsics.checkParameterIsNotNull(extras, "extras");
if (extras.length == 0) {
return $receiver;
} else {
Pair[] var3 = extras;
int var4 = extras.length;
int var5;
Pair element$iv;
boolean var8;
String key;
for(var5 = 0; var5 < var4; ++var5) {
element$iv = var3[var5];
var8 = false;
key = (String)element$iv.getFirst();
if (element$iv.getSecond() == null) {
int var12 = false;
$receiver.putExtra(key, $receiver.toString());
}
}
var3 = extras;
var4 = extras.length;
for(var5 = 0; var5 < var4; ++var5) {
element$iv = var3[var5];
var8 = false;
key = (String)element$iv.component1();
Object value = element$iv.component2();
if (value != null) {
if (value instanceof Bundle) {
$receiver.putExtra(key, (Bundle)value);
} else if (value instanceof Boolean) {
$receiver.putExtra(key, (Boolean)value);
} else if (value instanceof boolean[]) {
$receiver.putExtra(key, (boolean[])value);
} else if (value instanceof Byte) {
$receiver.putExtra(key, ((Number)value).byteValue());
} else if (value instanceof byte[]) {
$receiver.putExtra(key, (byte[])value);
} else if (value instanceof Character) {
$receiver.putExtra(key, (Character)value);
} else if (value instanceof char[]) {
$receiver.putExtra(key, (char[])value);
} else if (value instanceof String) {
$receiver.putExtra(key, (String)value);
} else if (value instanceof CharSequence) {
$receiver.putExtra(key, (CharSequence)value);
} else if (value instanceof Double) {
$receiver.putExtra(key, ((Number)value).doubleValue());
} else if (value instanceof double[]) {
$receiver.putExtra(key, (double[])value);
} else if (value instanceof Float) {
$receiver.putExtra(key, ((Number)value).floatValue());
} else if (value instanceof float[]) {
$receiver.putExtra(key, (float[])value);
} else if (value instanceof Integer) {
$receiver.putExtra(key, ((Number)value).intValue());
} else if (value instanceof int[]) {
$receiver.putExtra(key, (int[])value);
} else if (value instanceof Long) {
$receiver.putExtra(key, ((Number)value).longValue());
} else if (value instanceof long[]) {
$receiver.putExtra(key, (long[])value);
} else if (value instanceof Short) {
$receiver.putExtra(key, ((Number)value).shortValue());
} else if (value instanceof short[]) {
$receiver.putExtra(key, (short[])value);
} else if (value instanceof Object[]) {
if ((Object[])value instanceof String[]) {
$receiver.putStringArrayListExtra(key, (ArrayList)value);
} else if ((Object[])value instanceof CharSequence[]) {
$receiver.putCharSequenceArrayListExtra(key, (ArrayList)value);
} else if ((Object[])value instanceof Parcelable[]) {
$receiver.putParcelableArrayListExtra(key, (ArrayList)value);
}
} else if (value instanceof Parcelable) {
$receiver.putExtra(key, (Parcelable)value);
} else {
if (!(value instanceof Serializable)) {
throw (Throwable)(new IllegalArgumentException("Not support " + value + " type " + value.getClass() + ".."));
}
$receiver.putExtra(key, (Serializable)value);
}
} else {
int var13 = false;
$receiver.putExtra(key, $receiver.toString());
}
}
return $receiver;
}
}
}
順手寫別的擴充套件
既然用到Intent的擴充套件，那麼就順手寫下Activity的startActivity的擴充套件
/**
* 同Context的startActivity
*/
fun Context.toActivity(packageContext:Context?, cls:Class<*>,vararg extras: Pair<String, Any?>) {
startActivity(Intent(packageContext, cls).putExtraVararg(*extras))
}
/**
* 同Context的startActivity
*/
fun Context.toActivity(intent:Intent) {
startActivity(intent)
}
呼叫的時候就是這樣子的
context.toActivity( context, SearchActivity::class.java, SearchActivity.SEARCH_TYPE to item.type, SearchActivity.SEARCH_UID to item.uid, SearchActivity.SEARCH_NAME to item.name, SearchActivity.SEARCH_KEY to item.key, SearchActivity.SEARCH_GROUP to item.group )