Android reflection call resource and id

Android reflection call resource and id

This topic describes how to call resources and id Using Reflection.

Raise questions:

An app has an advertisement called an app wall. An app wall pops up an Activity in your app to display the advertisement, for example, petabytes of text, during integration, You need to copy the resources to your project, but the app wall code is encapsulated jar code. It is not the source code. It cannot be seen or modified. How does the Code in jar load local resources?

Authorization + CjwvcD4KPHA + zai5/dStyry1xGphdmG3tMnku/authorization + authorization = "brush: java;"> public class IDHelper {public static int getLayout (Context mContext, String layoutName) {return ResourceHelper. getInstance (mContext ). getLayoutId (layoutName);} public static int getViewID (Context mContext, String IDName) {return ResourceHelper. getInstance (mContext ). getId (IDName);} public static int getDrawable (Context context, String drawableName) {return ResourceHelper. getInstance (context ). getDrawableId (drawableName);} public static int getAttr (Context context, String attrName) {return ResourceHelper. getInstance (context ). getAttrId (attrName);} public static int getString (Context context, String stringName) {return ResourceHelper. getInstance (context ). getStringId (stringName );}}

ResourceHelper. java

public class ResourceHelper {private static ResourceHelper mResource = null;private static String mPackagename = null;private static Class
  mLayout = null;private static Class
  mDrawable = null;private static Class
  mID = null;private static Class
  mString = null;private static Class
  mAttr = null;public static ResourceHelper getInstance(Context context) {if (mResource == null) {mPackagename = (mPackagename == null ? context.getPackageName(): mPackagename);mResource = new ResourceHelper(mPackagename);}return mResource;}public ResourceHelper(String packageName) {try {mLayout = Class.forName(packageName + ".R$layout");} catch (ClassNotFoundException e) {e.printStackTrace();}try {mDrawable = Class.forName(packageName + ".R$drawable");} catch (ClassNotFoundException e) {e.printStackTrace();}try {mID = Class.forName(packageName + ".R$id");} catch (ClassNotFoundException e) {e.printStackTrace();}try {mString = Class.forName(packageName + ".R$string");} catch (ClassNotFoundException e) {e.printStackTrace();}try {mAttr = Class.forName(packageName + ".R$attr");} catch (ClassNotFoundException e) {e.printStackTrace();}}private int getResourceId(Class
  classType, String resourceName) {if (classType == null) {throw new IllegalArgumentException("ResClass is not initialized. Please make sure you have added neccessary resources. Also make sure you have "+ mPackagename+ ".R$* configured in obfuscation. field="+ resourceName);}try {Field field = classType.getField(resourceName);return field.getInt(resourceName);} catch (Exception e) {e.printStackTrace();Log.e("ResourceHelper","Error getting resource. Make sure you have copied all resources (res/) from SDK to your project.");}return -1;}//public int getDrawableId(String resourceName) {return getResourceId(mDrawable, resourceName);}public int getLayoutId(String resourceName) {return getResourceId(mLayout, resourceName);}public int getId(String resourceName) {return getResourceId(mID, resourceName);}public int getStringId(String resourceName) {return getResourceId(mString, resourceName);}public int getAttrId(String resourceName) {return getResourceId(mAttr, resourceName);}}

Usage:

You do not need to use R to call resources.

Public class MainActivity extends ActionBarActivity {private Button mButton; @ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (IDHelper. getLayout (getApplicationContext (), "activity_main"); // the string is the name of the layout file initView ();} private void initView () {mButton = (Button) findViewById (IDHelper. getViewID (getApplicationContext (), "button1"); mButton. setOnClickListener (new OnClickListener () {@ Overridepublic void onClick (View arg0) {Toast. makeText (getApplicationContext (), "HelloWorld", Toast. LENGTH_LONG ). show (); // the string is the Control id }});}}

How to obtain the id through reflection through the Android API

Context.getResources().getIdentifier("activity_main", "layout",                 paramContext.getPackageName());