support for Android InstantRun Apk

 we should consider the input file could contain only one single dex, multi-dex, or instantRun support dex for Android .apk files

jadx-core/src/main/java/jadx/core/utils/files/InputFile.java

@@ -10,6 +10,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.Enumeration;
 import java.util.List;
 import java.util.jar.JarOutputStream;
 import java.util.zip.ZipEntry;
@@ -81,36 +82,53 @@ public class InputFile {
 
 	private boolean loadFromZip(String ext) throws IOException, DecodeException {
 		ZipFile zf = new ZipFile(file);
+
+		// Input file could be .apk or .zip files
+		// we should consider the input file could contain only one single dex, multi-dex, or instantRun support dex for Android .apk files
+		String instantRunDexSuffix = "classes" + ext;
 		int index = 0;
-		while (true) {
-			String entryName = "classes" + (index == 0 ? "" : index) + ext;
-			ZipEntry entry = zf.getEntry(entryName);
-			if (entry == null) {
-				break;
-			}
+		for (Enumeration<? extends ZipEntry> e = zf.entries(); e.hasMoreElements(); ) {
+			ZipEntry entry = e.nextElement();
+			String entryName = entry.getName();
+
 			InputStream inputStream = zf.getInputStream(entry);
 			try {
-				if (ext.equals(".dex")) {
-					addDexFile(entryName, new Dex(inputStream));
-				} else if (ext.equals(".jar")) {
-					File jarFile = FileUtils.createTempFile(entryName);
+				if ((entryName.startsWith("classes") && entryName.endsWith(ext)) || entryName.endsWith(instantRunDexSuffix)) {
+					if (ext.equals(".dex")) {
+						index++;
+						addDexFile(entryName, new Dex(inputStream));
+					} else if (ext.equals(".jar")) {
+						index++;
+						File jarFile = FileUtils.createTempFile(entryName);
+						FileOutputStream fos = new FileOutputStream(jarFile);
+						try {
+							IOUtils.copy(inputStream, fos);
+						} finally {
+							close(fos);
+						}
+						addDexFile(entryName, loadFromJar(jarFile));
+					} else {
+						throw new JadxRuntimeException("Unexpected extension in zip: " + ext);
+					}
+				} else if (entryName.equals("instant-run.zip") && ext.equals(".dex")) {
+					File jarFile = FileUtils.createTempFile("instant-run.zip");
 					FileOutputStream fos = new FileOutputStream(jarFile);
 					try {
 						IOUtils.copy(inputStream, fos);
 					} finally {
 						close(fos);
 					}
-					addDexFile(entryName, loadFromJar(jarFile));
-				} else {
-					throw new JadxRuntimeException("Unexpected extension in zip: " + ext);
+					InputFile tempFile = new InputFile(jarFile);
+					tempFile.loadFromZip(ext);
+					List<DexFile> dexFiles = tempFile.getDexFiles();
+					if (!dexFiles.isEmpty()) {
+						index += dexFiles.size();
+						this.dexFiles.addAll(dexFiles);
+					}
 				}
 			} finally {
 				close(inputStream);
 			}
-			index++;
-			if (index == 1) {
-				index = 2;
-			}
 		}
 		zf.close();
 		return index > 0;