Java 如何获取具有已知资源名称的资源 ID？

How to get a resource id with a known resource name?

提问by Aswan

I want to access a resource like a String or a Drawable by its name and not its int id.

我想通过名称而不是 int id 访问像 String 或 Drawable 这样的资源。

Which method would I use for this?

我会使用哪种方法？

采纳答案by Rabid

It will be something like:

它会是这样的：

R.drawable.resourcename

R.drawable.resourcename

Make sure you don't have the Android.Rnamespace imported as it can confuse Eclipse (if that's what you're using).

确保您没有Android.R导入命名空间，因为它可能会混淆 Eclipse（如果这是您正在使用的）。

If that doesn't work, you can always use a context's getResourcesmethod ...

如果这不起作用，您始终可以使用上下文的getResources方法......

Drawable resImg = this.context.getResources().getDrawable(R.drawable.resource);

Where this.contextis intialised as an Activity, Serviceor any other Contextsubclass.

Wherethis.context初始化为Activity，Service或任何其他Context子类。

Update:

更新：

If it's the name you want, the Resourcesclass (returned by getResources()) has a getResourceName(int)method, and a getResourceTypeName(int)?

如果这是您想要的名称，则Resources类（由 返回getResources()）有一个getResourceName(int)方法，还有一个getResourceTypeName(int)?

Update 2:

更新2：

The Resourcesclass has this method:

这个Resources类有这个方法：

public int getIdentifier (String name, String defType, String defPackage) 

Which returns the integer of the specified resource name, type & package.

它返回指定资源名称、类型和包的整数。

回答by Maragues

If I understood right, this is what you want

如果我理解正确，这就是你想要的

int drawableResourceId = this.getResources().getIdentifier("nameOfDrawable", "drawable", this.getPackageName());

Where "this" is an Activity, written just to clarify.

其中“this”是一个活动，只是为了澄清而写的。

In case you want a String in strings.xml or an identifier of a UI element, substitute "drawable"

如果您想要 strings.xml 中的字符串或 UI 元素的标识符，请替换“drawable”

int resourceId = this.getResources().getIdentifier("nameOfResource", "id", this.getPackageName());

I warn you, this way of obtaining identifiers is really slow, use only where needed.

我警告你，这种获取标识符的方式真的很慢，只在需要的地方使用。

Link to official documentation: Resources.getIdentifier(String name, String defType, String defPackage)

官方文档链接：Resources.getIdentifier(String name, String defType, String defPackage)

回答by Lonkly

I would suggest you using my method to get a resource ID. It's Much more efficient, than using getIdentidier() method, which is slow.

我建议您使用我的方法来获取资源 ID。它比使用速度慢的 getIdentidier() 方法更有效。

Here's the code:

这是代码：

/**
 * @author Lonkly
 * @param variableName - name of drawable, e.g R.drawable.<b>image</b>
 * @param с - class of resource, e.g R.drawable.class or R.raw.class
 * @return integer id of resource
 */
public static int getResId(String variableName, Class<?> с) {

    Field field = null;
    int resId = 0;
    try {
        field = с.getField(variableName);
        try {
            resId = field.getInt(null);
        } catch (Exception e) {
            e.printStackTrace();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return resId;

}

回答by user1393422

int resourceID = 
    this.getResources().getIdentifier("resource name", "resource type as mentioned in R.java",this.getPackageName());

回答by Muhammad Adil

A simple way to getting resource ID from string. Here resourceName is the name of resource ImageView in drawable folder which is included in XML file as well.

从字符串中获取资源 ID 的简单方法。这里的 resourceName 是 drawable 文件夹中资源 ImageView 的名称，该文件夹也包含在 XML 文件中。

int resID = getResources().getIdentifier(resourceName, "id", getPackageName());
ImageView im = (ImageView) findViewById(resID);
Context context = im.getContext();
int id = context.getResources().getIdentifier(resourceName, "drawable",
context.getPackageName());
im.setImageResource(id);

回答by Diego Malone

I have found this classvery helpful to handle with resources. It has some defined methods to deal with dimens, colors, drawables and strings, like this one:

我发现这门课对处理资源非常有帮助。它有一些定义的方法来处理维度、颜色、可绘制对象和字符串，如下所示：

public static String getString(Context context, String stringId) {
    int sid = getStringId(context, stringId);
    if (sid > 0) {
        return context.getResources().getString(sid);
    } else {
        return "";
    }
}

回答by ceph3us

in addition to @lonkly solution

除了@lonkly 解决方案

1. see reflections and field accessibility
2. unnecessary variables

1. 查看反射和字段可访问性
2. 不必要的变量

method:

方法：

/**
 * lookup a resource id by field name in static R.class 
 * 
 * @author - ceph3us
 * @param variableName - name of drawable, e.g R.drawable.<b>image</b>
 * @param с            - class of resource, e.g R.drawable.class or R.raw.class
 * @return integer id of resource
 */
public static int getResId(String variableName, Class<?> с)
                     throws android.content.res.Resources.NotFoundException {
    try {
        // lookup field in class 
        java.lang.reflect.Field field = с.getField(variableName);
        // always set access when using reflections  
        // preventing IllegalAccessException   
        field.setAccessible(true);
        // we can use here also Field.get() and do a cast 
        // receiver reference is null as it's static field 
        return field.getInt(null);
    } catch (Exception e) {
        // rethrow as not found ex
        throw new Resources.NotFoundException(e.getMessage());
    }
}

回答by aminography

? Kotlin Versionvia Extension Function

? Kotlin Version通过Extension Function

To find a resource id by its name In Kotlin, add below snippet in a kotlin file:

要按名称查找资源 ID 在 Kotlin 中，请在 kotlin 文件中添加以下代码段：

ExtensionFunctions.kt

扩展函数.kt

import android.content.Context
import android.content.res.Resources

fun Context.resIdByName(resIdName: String?, resType: String): Int {
    resIdName?.let {
        return resources.getIdentifier(it, resType, packageName)
    }
    throw Resources.NotFoundException()
}

? Usage

? Usage

Now all resource ids are accessible wherever you have a context reference using resIdByNamemethod:

现在，只要您使用resIdByName方法有上下文引用，就可以访问所有资源 ID ：

val drawableResId = context.resIdByName("ic_edit_black_24dp", "drawable")
val stringResId = context.resIdByName("title_home", "string")
.
.
.    

回答by Manthan Patel

// image from res/drawable
    int resID = getResources().getIdentifier("my_image", 
            "drawable", getPackageName());
// view
    int resID = getResources().getIdentifier("my_resource", 
            "id", getPackageName());

// string
    int resID = getResources().getIdentifier("my_string", 
            "string", getPackageName());