android-metadata

Additional

Language
Java
Version
1.5.1 (Aug 5, 2016)
Created
Feb 13, 2014
Updated
Nov 13, 2018 (Retired)
Owner
One Hill Technologies, LLC (onehilltech)
Contributors
Vladislav Bauer (vbauer)
James H. Hill (hilljh82)
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android-metadata

A utility library for Android designed to simplify reading meta-data values from AndroidManifest.xml.

  • Quickly access a meta-data values from anywhere with few lines of code.
  • Read individual meta-data values into type-specific variables.
  • Instantiate objects from meta-data values.
  • Read one or more meta-data values into annotated Java classes.
  • Use meta-data values to pass configuration parameters to third-party libraries.

Installation

Gradle

buildscript {
  repositories {
    maven { url "https://jitpack.io" }
  }
}

dependencies {
  compile com.github.onehilltech:android-metadata:x.y.z
}

Getting Started

Here is the quickest and easiest way to load the metadata from AndroidManifest.xml and get a value. The value, by default, is a String value type.

ManifestMetadata metadata = ManifestMetadata.get (context);

// <meta-data android:name="appid" android:value="32ba65ae723940" />
String value = metadata.getValue ("appid");

If the value is not a String type, then you can provide a hint:

ManifestMetadata metadata = ManifestMetadata.get (context);

// <meta-data android:name="conn.timeout" android:value="60" />
Integer connTimeout = metadata.getValue ("conn.timeout", Integer.class);

You can even directly load a resource from the metadata:

ManifestMetadata metadata = ManifestMetadata.get (context);

// <meta-data android:name="appname" android:resource="@string/app_name" />
String appName = metadata.getValue ("appname", true, String.class);

In some cases, you may need to provide additional information about the resource type since different resources types can have the same Java type:

ManifestMetadata metadata = ManifestMetadata.get (context);

// <meta-data android:name="bgcolor" android:resource="@color/background" />
Integer bgColor = metadata.getValue ("bgcolor", true, Integer.class, ResourceType.Color);

Using Annotations to Load Metadata

Here is the simplest example of using an annotation to define what meta-data value in AndroidManifest.xml it should be initialized with:

public class MyData {
  private String appid_;
  
  @MetadataProperty (name="my.message")
  public String message;
  
  @MetadataMethod (name="appid")
  public void setAppId (String appid) {
    this.appid_ = appid;
  }
}

In the example above, the field message will be initialized with the value of meta-data tag named my.message. You initialize all values with the @Metadata annotation using a single line of code:

MyData myData = new MyData ();
ManifestMetadata.get (context).initFromMetadata (myData);

This method will auto-detect the target type, and then assign the value. If the field is not assignable using the meta-data's value, then an exception will be thrown.

Reading from a Resource

In some cases, you will want to read the value from a resource (i.e., you use android:resource in the meta-data tag). You can use the @Metadata annotation to read resource values as well:

public class MyData {
  private String appid_;
  
  @MetadataProperty (name="my.message", fromResource=true)
  public String message;

  @MetadataMethod (name="appid", fromResource=true)
  public void setAppId (String appid) {
    this.appid_ = appid;
  }
}

Giving Resource Type Hints

There are some resources that have the same field type, such as integer and color. This makes it hard to auto-detect the resources type. We can therefore provide a hint as follows:

public class MyData {
  @MetadataProperty (name="my.message", fromResource=true, resourceType=ResourceType.Color)
  public int backgroundColor;
}

In the example above, the value for backgroundColor will be loaded from resources and interpreted as a color.