Android：如何将Enum放入捆绑包中？

Question

如何将Enum对象添加到Android Bundle？

Answer 1

枚举是可序列化的，所以没有问题。

鉴于以下枚举：

enum YourEnum {
  TYPE1,
  TYPE2
}

软件包：

// put
bundle.putSerializable("key", YourEnum.TYPE1);

// get 
YourEnum yourenum = (YourEnum) bundle.get("key");

意图：

// put
intent.putExtra("key", yourEnum);

// get
yourEnum = (YourEnum) intent.getSerializableExtra("key");

Answer 2

我知道这是一个老问题，但我遇到了同样的问题，我想分享一下我是如何解决它的。关键是米格尔所说的：枚举是可序列化的。

鉴于以下枚举：

enum YourEnumType {
    ENUM_KEY_1, 
    ENUM_KEY_2
}

把：

Bundle args = new Bundle();
args.putSerializable("arg", YourEnumType.ENUM_KEY_1);

Answer 3

为了完整起见，这是一个完整的例子，说明如何从包中输入和获取枚举。

鉴于以下枚举：

enum EnumType{
    ENUM_VALUE_1,
    ENUM_VALUE_2
}

您可以将枚举放入捆绑包中：

bundle.putSerializable("enum_key", EnumType.ENUM_VALUE_1);

然后回复：

EnumType enumType = (EnumType)bundle.getSerializable("enum_key");

Answer 4

我用kotlin。

companion object {

        enum class Mode {
            MODE_REFERENCE,
            MODE_DOWNLOAD
        }
}

然后进入意图：

intent.putExtra(KEY_MODE, Mode.MODE_DOWNLOAD.name)

当你净获得价值时：

mode = Mode.valueOf(intent.getStringExtra(KEY_MODE))

Answer 5

最好从myEnumValue.name（）传递它作为字符串并从YourEnums.valueOf（s）恢复它，否则必须保留枚举的顺序！

更长的解释：Convert from enum ordinal to enum type

Answer 6

另一种选择：

public enum DataType implements Parcleable {
    SIMPLE, COMPLEX;

    public static final Parcelable.Creator<DataType> CREATOR = new Creator<DataType>() {

        @Override
        public DataType[] newArray(int size) {
            return new DataType[size];
        }

        @Override
        public DataType createFromParcel(Parcel source) {
            return DataType.values()[source.readInt()];
        }
    };

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(this.ordinal());
    }
}

Answer 7

使用bundle.putSerializable（String key，Serializable s）和bundle.getSerializable（String key）：

enum Mode = {
  BASIC, ADVANCED
}

Mode m = Mode.BASIC;

bundle.putSerializable("mode", m);

...

Mode m;
m = bundle.getSerializable("mode");

文档：http://developer.android.com/reference/android/os/Bundle.html

Answer 8

有一点需要注意 - 如果您使用#include<stdio.h> #include<dirent.h> #include<sys/stat.h> #include<errno.h> #include<string.h> #include<stdlib.h> #include<fcntl.h> //Compile: gcc dreamduplicatefinder.c -o dreamduplicatefinder.exe //Run: ./dreamduplicateFinder.exe parent_dir filename... #define false 0 #define true 1 int duplicateCount = 0; int FindDuplicates(char* path, char* fileName); int CompareFiles(char* originalFile, char* currFile); int main(int argc, char *argv[]) { //Two additional arguments are expected: Parent dir, file to find duplicates of... if (argc != 3) { printf("Usage: %s 'Base Directory' 'File Name'\n", argv[0]); return -1; } //argv[1] = base dir, argv[2] = file to find duplicates of; e.g argv[1] = /home, //argv[2] = "file.txt"... FindDuplicates(argv[1], argv[2]); printf("\n\nFound %d duplicate(s)\n", duplicateCount); return 0; } int FindDuplicates(char* path, char* fileName) { DIR *dir; struct dirent *dp; struct dirent *result; struct stat statp; char absoluteFilePath[255]; if ((dir = opendir(path)) == NULL) { //printf(dir); //error could becuase trying to open shortcut or corrupt folder. printf("%s\n",path); perror("Failed to open directory"); return -1; } while ((dp = readdir(dir)) != NULL) { //readdir returns . and .. which we should ignore... if (strcmp(dp->d_name, ".") && strcmp(dp->d_name, "..")) { //find file full path, relative to base path. e.g, a /home/file.txt... //copy path to absoluteFilePath... strcpy(absoluteFilePath, path); //append / at end... strcat(absoluteFilePath, "/"); //append filename to path... strcat(absoluteFilePath, dp->d_name); //check if the current file is actually file or dir... stat(absoluteFilePath, &statp); if (S_ISDIR(statp.st_mode)) //is a directory... { //recurse through this dir... FindDuplicates(absoluteFilePath, fileName); } else if (S_ISREG(statp.st_mode)) //is a file... { //check for duplicates here... //compare current file with the file specified by user... if (strcmp(fileName, absoluteFilePath)) { if (CompareFiles(fileName, absoluteFilePath)) { //yes, duplicate; print it... printf("%s\n", absoluteFilePath); duplicateCount++; } } } //end else if (S_ISREG(statp.st_mode))... } //if (strcmp(dp->d_name, ".") && strcmp(dp->d_name,".."))... } //end while... closedir(dir); return 0; } int CompareFiles(char* originalFile, char* currFile) { //two step comparison: (1) first check size; if not same, return false. //If equal, (2) compare file content.If equal, return true, false otherwise... struct stat statOriginal, statCurr; stat(originalFile, &statOriginal); stat(currFile, &statCurr); //Step 1... if ((int)statOriginal.st_size != (int)statCurr.st_size) //size not same... return false; //Step 2... //size matches, files can be same; confirm it by matching both file contents... int fdOriginal = open(originalFile, O_RDONLY); int fdCurr = open(currFile, O_RDONLY); if (fdOriginal == -1 || fdCurr == -1) return false; //error occurred, not sure if file is duplicate... //we will read file in small chunks and compare... int chunkSize = 1024, bytesRead; char *bufferOriginal = (char*)malloc(chunkSize * sizeof(char)); char *bufferCurr = (char*)malloc(chunkSize * sizeof(char)); while (true) { //read file in chunk... bytesRead = read(fdOriginal, bufferOriginal, chunkSize); if (bytesRead <= 0) break; //end of file... bytesRead = read(fdCurr, bufferCurr, bytesRead); //compare buffer... if (strcmp(bufferOriginal, bufferCurr)) //if content not matching... return false; } return true; } 将#include "stdafx.h" //there is nothing in this header #include<stdio.h> #include<dirent.h> #include<sys/stat.h> #include<errno.h> #include<string.h> #include<stdlib.h> #include<fcntl.h> #include <iostream> #include <fstream> #include <string> using namespace std; //Compile: gcc <name of this file>.cpp -o <nameOfThisFile>.exe //Run: <nameOfThisFile> parent_dir filename... #define false 0 #define true 1 int duplicateCount = 0; int FindDuplicates(char* path, char* fileName); int CompareFiles(char* originalFile, char* currFile); int main(int argc, char *argv[]) { //Two additional arguments are expected: Parent dir, file to find duplicates of... if (argc != 3) { printf("Usage: %s 'Base Directory' 'File Name'\n", argv[0]); return -1; } //argv[1] = base dir, argv[2] = file to find duplicates of; e.g argv[1] = /home, //argv[2] = "file.txt"... FindDuplicates(argv[1], argv[2]); printf("\n\nFound %d duplicate(s)\n", duplicateCount); return 0; } int FindDuplicates(char* path, char* fileName) { DIR *dir; struct dirent *dp; struct dirent *result; struct stat statp; char absoluteFilePath[255]; if ((dir = opendir(path)) == NULL) { //possibly trying to open shortcut or corrupt folder typically. printf("Failed to open directory %s \n",path); return -1; } while ((dp = readdir(dir)) != NULL) { //readdir returns . and .. which we should ignore... if (strcmp(dp->d_name, ".") && strcmp(dp->d_name, "..")) { //find file full path, relative to base path. e.g, a /home/file.txt... //copy path to absoluteFilePath... strcpy(absoluteFilePath, path); //append / at end... strcat(absoluteFilePath, "/"); //append filename to path... strcat(absoluteFilePath, dp->d_name); //check if the current file is actually file or dir... stat(absoluteFilePath, &statp); if (S_ISDIR(statp.st_mode)) //is a directory... { //recurse through this dir... FindDuplicates(absoluteFilePath, fileName); } else if (S_ISREG(statp.st_mode)) //is a file... { //check for duplicates here... //compare current file with the file specified by user... if (strcmp(fileName, absoluteFilePath)) { if (CompareFiles(fileName, absoluteFilePath)) { //yes, duplicate; print it... printf("This is a duplicate! %s\n", absoluteFilePath); duplicateCount++; } } } //end else if (S_ISREG(statp.st_mode))... } //if (strcmp(dp->d_name, ".") && strcmp(dp->d_name,".."))... } //end while... closedir(dir); return 0; } int CompareFiles(char* originalFile, char* currFile) { //two step comparison: (1) first check size; if not same, return false. //If equal, (2) compare file content.If equal, return true, false otherwise... struct stat statOriginal, statCurr; stat(originalFile, &statOriginal); stat(currFile, &statCurr); //Step 1... if ((int)statOriginal.st_size != (int)statCurr.st_size) //size not same... return false; FILE* fdOriginal; if (fdOriginal = fopen(originalFile, "r")) { if (fdOriginal == NULL) { fputs("File error", stderr); return false; } } else return false; //error occurred, not sure if duplicate FILE* fdCurr; if (fdCurr = fopen(currFile, "r")) { if (fdCurr == NULL) { fputs("File error", stderr); return false; } } else return false; int chunkSize = 1024, objsRead; char *bufferOriginal = (char*)malloc(chunkSize * sizeof(char)); if (bufferOriginal == NULL) { fputs("Memory error for buff orig", stderr); exit(2); } char *bufferCurr = (char*)malloc(chunkSize * sizeof(char)); if (bufferCurr == NULL) { fputs("Memory error for buff curr", stderr); exit(2); } while (true) { //read file in chunk... //std::size_t fread( void* buffer, std::size_t size, std::size_t count, std::FILE* stream ); objsRead = fread(bufferOriginal, sizeof(char), chunkSize , fdOriginal); if (objsRead <= 0) break; //end of file... objsRead = fread(bufferCurr, sizeof(char), objsRead, fdCurr); //compare buffer... if (strcmp(bufferOriginal, bufferCurr)) //if content not matching... return false; } return true; } 添加到通知中，则可能会遇到以下问题：

bundle.putSerializable

要解决此问题，您可以执行以下操作：

Bundle

然后可以这样使用：

*** Uncaught remote exception!  (Exceptions are not yet supported across processes.)
    java.lang.RuntimeException: Parcelable encountered ClassNotFoundException reading a Serializable object.

...

Answer 9

对于意图，您可以使用以下方式：

意图：科特林

FirstActivity：

val intent = Intent(context, SecondActivity::class.java)
intent.putExtra("type", typeEnum.A)
startActivity(intent)

SecondActivity：

override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState) 
     //...
     val type = (intent.extras?.get("type") as? typeEnum.Type?)
}

Answer 10

我创建了Koltin扩展名：

key

创建一个包并添加：

fun Bundle.putEnum(key: String, enum: Enum<*>) {
    this.putString( key , enum.name )
}

inline fun <reified T: Enum<T>> Intent.getEnumExtra(key:String) : T {
    return enumValueOf( getStringExtra(key) )
}

并获取：

Bundle().also {
   it.putEnum( "KEY" , ENUM_CLAS.ITEM )
}

Answer 11

一种简单的方法，将整数值赋给枚举

请参阅以下示例：

public enum MyEnum {

    TYPE_ONE(1), TYPE_TWO(2), TYPE_THREE(3);

    private int value;

    MyEnum(int value) {
        this.value = value;
    }

    public int getValue() {
        return value;
    }

}

发件人方：

Intent nextIntent = new Intent(CurrentActivity.this, NextActivity.class);
nextIntent.putExtra("key_type", MyEnum.TYPE_ONE.getValue());
startActivity(nextIntent);

接收方：

Bundle mExtras = getIntent().getExtras();
int mType = 0;
if (mExtras != null) {
    mType = mExtras.getInt("key_type", 0);
}

/* OR
    Intent mIntent = getIntent();
    int mType = mIntent.getIntExtra("key_type", 0);
*/

if(mType == MyEnum.TYPE_ONE.getValue())
    Toast.makeText(NextActivity.this, "TypeOne", Toast.LENGTH_SHORT).show();
else if(mType == MyEnum.TYPE_TWO.getValue())
    Toast.makeText(NextActivity.this, "TypeTwo", Toast.LENGTH_SHORT).show();
else if(mType == MyEnum.TYPE_THREE.getValue())
    Toast.makeText(NextActivity.this, "TypeThree", Toast.LENGTH_SHORT).show();
else
    Toast.makeText(NextActivity.this, "Wrong Key", Toast.LENGTH_SHORT).show();

Answer 12

我认为将enum转换为int（对于普通的枚举）然后在bundle上设置是最简单的方法。喜欢这个意图代码：

myIntent.PutExtra("Side", (int)PageType.Fornt);

然后检查状态：

int type = Intent.GetIntExtra("Side",-1);
if(type == (int)PageType.Fornt)
{
    //To Do
}

但不适用于所有枚举类型！

Answer 13

从ordinal（）传递int。从值[]恢复它。