如何在 android 中通过名称访问可绘制的资源

在我的应用程序中，我需要得到一些位图绘制的地方，我不想保持参考 R。因此，我创建了一个类 DrawableManager来管理这些绘图工具。

public class DrawableManager {
private static Context context = null;


public static void init(Context c) {
context = c;
}


public static Drawable getDrawable(String name) {
return R.drawable.?
}
}

然后我想通过名称来获取可绘制的内容，如下所示(car.png 放在 res/draables 中) :

Drawable d= DrawableManager.getDrawable("car.png");

然而，正如您所看到的，我无法通过名称访问资源:

public static Drawable getDrawable(String name) {
return R.drawable.?
}

还有别的选择吗？

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最佳答案

Note that your approach is almost always the wrong way to do things (better to pass the context into the object itself that is using the drawable than keeping a static Context somewhere).

Given that, if you want to do dynamic drawable loading, you can use getIdentifier:

Resources resources = context.getResources();
final int resourceId = resources.getIdentifier(name, "drawable",
context.getPackageName());
return resources.getDrawable(resourceId);
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You could do something like this.-

public static Drawable getDrawable(String name) {
Context context = YourApplication.getContext();
int resourceId = context.getResources().getIdentifier(name, "drawable", YourApplication.getContext().getPackageName());
return context.getResources().getDrawable(resourceId);
}

In order to access the context from anywhere, you may extend Application class.-

public class YourApplication extends Application {


private static YourApplication instance;


public YourApplication() {
instance = this;
}


public static Context getContext() {
return instance;
}
}

And map it in your Manifest application tag

<application
android:name=".YourApplication"
....
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Modify image content:

    ImageView image = (ImageView)view.findViewById(R.id.imagenElement);
int resourceImage = activity.getResources().getIdentifier(element.getImageName(), "drawable", activity.getPackageName());
image.setImageResource(resourceImage);
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Using Kotlin 

fun Context.getResource(name:String): Drawable? {
val resID = this.resources.getIdentifier(name , "drawable", this.packageName)
return ActivityCompat.getDrawable(this,resID)
}

I wrote it as Extension function so It can be used at any place in code.

Note: context.getResources().getDrawable(resourceId); is deprecated in Java.

Note: name of file,is name without extensions for ex "a.png" name will be "a".

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if You need int resouce

 Resources resources = context.getResources();
int resourceId = resources.getIdentifier("eskb048", "drawable",context.getPackageName());
// return like: R.drawable.eskb048.png

if your need Drawable check the first answer is correct for all

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You can achieve like this

int resourceId = getResources().getIdentifier("your_drawable_name", "drawable", getPackageName());

Set resourceId In Imageview

imageView.setImageResource(resourceId);
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The best solution would be to create a map of your icons in your code

val iconMap: HashMap<String, Int>

String is your key (to that drawable resource) that you can keep in your database, or even the key from backend API response

Int is the resource drawable

iconMap.put("cat", R.drawable.ic_cat)
iconMap.getOrDefault("dog", R.drawable.empty)

This way you make resource usage more visible to other devs


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