Quote:
Originally Posted by SyreKron
Jonny,
Sounds great. I don't really know where to start. I'd love to be able to use android text note and keyboard aps on my reader. That would allow me to leave one of my 3 regularly carried devices at home 
Google gives me too many results. How does one get started "opening" a closed android like this?
-SyreKron |
Ok, reverse engineering android apps is complicated but there are many tools to help with this.
Personally I use Virtuous Ten Studio made by a developer team on XDA. However, for first time users I would recommend using straight apktool.jar file as VTS is mainly for advanced users. apktool is available free and opensource from
here and is called from a command prompt (java -jar apktool.jar d apkname.apk).
A guide to using apktool (the commands have been incorporated into batch files to save typing it every time) can be found
here
Apk files consist of 2 parts, code and resources. Resources are your images, layouts, xml preferences, integers, strings, arrays etc. If you add something to the resources you must also create a new hex value for it in res/values/public.xml
The code part once decompiled is in a language called smali which is basically the dalvik bytecode (or an easier way of thinking of it is java's version of ASM) and its not the easiest language to understand, the below sample is part of a hack or modification that allows the current foreground application to be killed and removed from RAM by long pressing the back key, this is just to give you an example of what smali code looks like with regards its function:
Code:
.method private launchBackKeyLongPressAction()V
.locals 18
const/4 v1, 0x0
const/4 v2, 0x0
:try_start_0
move-object/from16 v0, p0
invoke-virtual {v0, v1, v2, v2}, Lcom/android/internal/policy/impl/PhoneWindowManager;->performHapticFeedbackLw(Landroid/view/WindowManagerPolicy$WindowState;IZ)Z
invoke-static {}, Landroid/app/ActivityManagerNative;->getDefault()Landroid/app/IActivityManager;
move-result-object v9
invoke-interface {v9}, Landroid/app/IActivityManager;->getRunningAppProcesses()Ljava/util/List;
move-result-object v5
move-object/from16 v0, p0
iget-object v14, v0, Lcom/android/internal/policy/impl/PhoneWindowManager;->mContext:Landroid/content/Context;
const-string v15, "activity"
invoke-virtual {v14, v15}, Landroid/content/Context;->getSystemService(Ljava/lang/String;)Ljava/lang/Object;
move-result-object v2
check-cast v2, Landroid/app/ActivityManager;
const/4 v14, 0x1
invoke-virtual {v2, v14}, Landroid/app/ActivityManager;->getRunningTasks(I)Ljava/util/List;
move-result-object v12
const/4 v14, 0x0
invoke-interface {v12, v14}, Ljava/util/List;->get(I)Ljava/lang/Object;
move-result-object v14
check-cast v14, Landroid/app/ActivityManager$RunningTaskInfo;
iget-object v6, v14, Landroid/app/ActivityManager$RunningTaskInfo;->topActivity:Landroid/content/ComponentName;
invoke-interface {v5}, Ljava/util/List;->iterator()Ljava/util/Iterator;
move-result-object v14
:cond_0
:goto_0
invoke-interface {v14}, Ljava/util/Iterator;->hasNext()Z
move-result v15
if-nez v15, :cond_2
:cond_1
:goto_1
return-void
:cond_2
invoke-interface {v14}, Ljava/util/Iterator;->next()Ljava/lang/Object;
move-result-object v3
check-cast v3, Landroid/app/ActivityManager$RunningAppProcessInfo;
iget v13, v3, Landroid/app/ActivityManager$RunningAppProcessInfo;->uid:I
const/16 v15, 0x2710
if-lt v13, v15, :cond_0
const v15, 0x1869f
if-gt v13, v15, :cond_0
iget v15, v3, Landroid/app/ActivityManager$RunningAppProcessInfo;->importance:I
const/16 v16, 0x64
move/from16 v0, v16
if-ne v15, v0, :cond_0
iget-object v15, v3, Landroid/app/ActivityManager$RunningAppProcessInfo;->pkgList:[Ljava/lang/String;
if-eqz v15, :cond_0
invoke-interface {v5}, Ljava/util/List;->size()I
move-result v15
if-lez v15, :cond_0
iget-object v15, v3, Landroid/app/ActivityManager$RunningAppProcessInfo;->processName:Ljava/lang/String;
invoke-virtual {v6}, Landroid/content/ComponentName;->getPackageName()Ljava/lang/String;
move-result-object v16
invoke-virtual/range {v15 .. v16}, Ljava/lang/String;->equals(Ljava/lang/Object;)Z
move-result v15
if-eqz v15, :cond_0
new-instance v8, Landroid/content/Intent;
const-string v15, "android.intent.action.MAIN"
invoke-direct {v8, v15}, Landroid/content/Intent;-><init>(Ljava/lang/String;)V
const-string v15, "android.intent.category.HOME"
invoke-virtual {v8, v15}, Landroid/content/Intent;->addCategory(Ljava/lang/String;)Landroid/content/Intent;
move-object/from16 v0, p0
iget-object v15, v0, Lcom/android/internal/policy/impl/PhoneWindowManager;->mContext:Landroid/content/Context;
invoke-virtual {v15}, Landroid/content/Context;->getPackageManager()Landroid/content/pm/PackageManager;
move-result-object v15
const/16 v16, 0x0
move/from16 v0, v16
invoke-virtual {v15, v8, v0}, Landroid/content/pm/PackageManager;->resolveActivity(Landroid/content/Intent;I)Landroid/content/pm/ResolveInfo;
move-result-object v11
iget-object v15, v11, Landroid/content/pm/ResolveInfo;->activityInfo:Landroid/content/pm/ActivityInfo;
iget-object v15, v15, Landroid/content/pm/ActivityInfo;->processName:Ljava/lang/String;
iget-object v0, v3, Landroid/app/ActivityManager$RunningAppProcessInfo;->processName:Ljava/lang/String;
move-object/from16 v16, v0
invoke-virtual/range {v15 .. v16}, Ljava/lang/String;->equals(Ljava/lang/Object;)Z
move-result v15
if-nez v15, :cond_1
move-object/from16 v0, p0
iget-object v15, v0, Lcom/android/internal/policy/impl/PhoneWindowManager;->mContext:Landroid/content/Context;
invoke-virtual {v15}, Landroid/content/Context;->getPackageManager()Landroid/content/pm/PackageManager;
:try_end_0
.catch Ljava/lang/Exception; {:try_start_0 .. :try_end_0} :catch_0
move-result-object v10
:try_start_1
invoke-virtual {v6}, Landroid/content/ComponentName;->getPackageName()Ljava/lang/String;
move-result-object v15
const/16 v16, 0x0
move/from16 v0, v16
invoke-virtual {v10, v15, v0}, Landroid/content/pm/PackageManager;->getApplicationInfo(Ljava/lang/String;I)Landroid/content/pm/ApplicationInfo;
:try_end_1
.catch Ljava/lang/Exception; {:try_start_1 .. :try_end_1} :catch_1
move-result-object v1
:goto_2
if-eqz v1, :cond_3
:try_start_2
invoke-virtual {v10, v1}, Landroid/content/pm/PackageManager;->getApplicationLabel(Landroid/content/pm/ApplicationInfo;)Ljava/lang/CharSequence;
move-result-object v4
:goto_3
check-cast v4, Ljava/lang/String;
invoke-virtual {v6}, Landroid/content/ComponentName;->getPackageName()Ljava/lang/String;
move-result-object v15
invoke-static {}, Landroid/os/UserHandle;->myUserId()I
move-result v0
invoke-interface {v9, v15, v0}, Landroid/app/IActivityManager;->forceStopPackage(Ljava/lang/String;I)V
iget v15, v3, Landroid/app/ActivityManager$RunningAppProcessInfo;->pid:I
invoke-static {v15}, Landroid/os/Process;->killProcess(I)V
new-instance v16, Ljava/lang/StringBuilder;
invoke-static {v4}, Ljava/lang/String;->valueOf(Ljava/lang/Object;)Ljava/lang/String;
move-result-object v17
invoke-direct/range {v16 .. v17}, Ljava/lang/StringBuilder;-><init>(Ljava/lang/String;)V
const-string v17, " killed."
invoke-virtual/range {v16 .. v17}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;
move-result-object v16
invoke-virtual/range {v16 .. v16}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;
move-result-object v16
move-object/from16 v0, p0
move-object/from16 v3, v16
iput-object v3, v0, Lcom/android/internal/policy/impl/PhoneWindowManager;->mKillMessage:Ljava/lang/String;
const-string v0, "DarkSense"
invoke-static {v0, v3}, Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I
move-object/from16 v0, p0
iget-object v2, v0, Lcom/android/internal/policy/impl/PhoneWindowManager;->mHandler:Landroid/os/Handler;
iget-object v3, v0, Lcom/android/internal/policy/impl/PhoneWindowManager;->mKill_Toast:Ljava/lang/Runnable;
invoke-static {}, Landroid/view/ViewConfiguration;->getGlobalActionKeyTimeout()J
move-result-wide v7
invoke-virtual {v2, v3, v7, v8}, Landroid/os/Handler;->postDelayed(Ljava/lang/Runnable;J)Z
goto/16 :goto_0
:catch_0
move-exception v14
goto/16 :goto_1
:catch_1
move-exception v7
const/4 v1, 0x0
goto :goto_2
:cond_3
const-string v4, "(unknown)"
:try_end_2
.catch Ljava/lang/Exception; {:try_start_2 .. :try_end_2} :catch_0
goto :goto_3
move-exception v0
const-string v2, "WindowManager"
const-string v3, "No activity to handle backkey action."
invoke-static {v2, v3, v0}, Landroid/util/Slog;->w(Ljava/lang/String;Ljava/lang/String;Ljava/lang/Throwable;)I
goto/16 :goto_1
.end method