[Android] Development FAQ

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1. Development
1. [Issue] Application crush when return from predefined interface
   [Solution 1] You may forgot to call the method of predefined super class
   i.e.: In your Activity, if you override onDestroy as following:
   class YourActivity extends Activity
   {
       protected void onDestroy()
       {
       }
   }
   when the activity is destroyed, application will crash, in order to resolve this issue, you must modify the code snip to:
   class YourActivity extends Activity
   {
       protected void onDestroy()
       {
           super.onDestroy();  //Call the same method of super class
       }
   }
   
2. [Issue] Explain view's attributes
      android:gravity: Define which direction to align control's contents.
   
3. [Issue] How to get and Set system property
   [Solution] Use methods System.getProperty(xxx) and System.setProperty(xxx), following properties can be got and set:
           java.vendor.url
           java.class.path
           user.home
           java.class.version
           os.version
           java.vendor
           user.dir
           user.timezone
           path.separator
           os.name
           os.arch
           line.separator
           file.separator
           user.name
           java.version
           java.home
   
4. [Issue] How to get popular directories and their stat
   [Sulotion] Call method android.os.Environment, following directories can be received:
      a) root directory
      b) external storage directory
      c) data directory
      d) download cache directory
      e) external storage state, 
   Note: USB mass storage path is /sdcard
   
5. [Issue] How to access resource in package in Acrivity
   - Get resource value
      getResources().getString(resID);  //resID looks like R.string.str_id
   - Get resource id from name
      getResources().getIdentifier("name", "string", getPackageName());
      getResources().getIdentifier("name", "drawable", getPackageName());
   
6. [Issue] How to get and  set environment variables
   [Solution] To get the value of the specified environment variables, just use System.getenv(xxx); But you can't set environment variable in Java code directly, you need to use jni to call C function 'setenv'.
   
7. [Issue] How to know byte order of device
   [Solution] Call method ByteOrder.nativeOrder();
   
8. [Issue] How to read files in the directories res/raw
   [Sulotion]
   Resources res = getResources();
   InputStream is = res.openRawResource(R.raw.xxx);
   
9. [Issue] How to display horizontal bar in widget
   [Solution] Use a view which background is filled with the specified color.
   
      
          ......
      
       ......
               android:background="#FF909090" />
       ......
   
   
   Comments:
   1) A control View with the specified background is shown as a bar
   2) The View must be declared within TableLayout
   3) If your want to implement the horizontal bar with left/right edges fading just like ListView's divider, you only need to set android:background to "?android:attr/listDivider"
   
   
10. [Issue] How to change contents of TextView
    - Set text view to be editable
        TextView textView = findViewById(xxx);
        textView.setText(textView.getText(), TextView.BufferType.EDITABLE);
    - Change contents
        textView.setText(xxx);
        textView.append(xxx);
11. [Issue] Customize View
     - Define customized view class as following
        package com.test.customized;
        import xxxxxx;
        class CustomizedTextView
        {
            private static String HEADER = "(Warning)";
            private static String RETURN = "\n";
    
    
            public TextView(Context context)
            {
                super(context);
            }
       
            public TextView(Context context, AttributeSet attrs)
            {
                super(context, attrs);
            }
    
            public TextView(Context context, AttributeSet attrs, int     defStyle)
            {
                super(context, attrs, defStyle);
            }
    
    
            public void append(CharSequence text, int start, int end)
            {
                super.append(HEADER, 0, HEADERS.length());
                super.append(text, start, end);
                super.append(RETURN, 0, RETURN.length());
            }
        }
    
    - Use the customized view as following
       
              xmlns:android=""
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:text="Hello, Android"/>
    
12. [Issue] How to use multiple Activity
    [Solution] Please refer to:
    
    http://blog.csdn.net/Class_Raito/archive/2008/11/27/3390737.aspx
13. [Issue] How to launch activity
    [Solution]
    Launch application
    1) From shell
      usage: am [start|instrument]
           am start [-a ] [-d ] [-t ]
                    [-c [-c ] ...]
                    [-e [-e ...]
                    [-n ] [-D] []
           am instrument [-e ] [-p ]
                    [-w]
           
    For example, launch an application whose manifest are:
           
    
      
       
           
               
                    
             
           
       
    
           
    Command is: #am start -n net.xiashou.android/net.xiashou.android.HelloAndroid     
    
    Other usage:
    a) Launch browser to open an URI: #am start -a android.intent.action.VIEW -d
    b) Call out: #am start -a android.intent.action.CALL -d tel:10086
    c) Launch google map to locate TianJing: #am start -a android.intent.action.VIEW geo:0,0?q=tianjin
    
    2) From on activate:
    Use Intent.
    For example, launch an activate whose manifest is:
    
        package="koushikdutta.superuser" android:versionCode="1"
        android:versionName="1.0.0">
    
                android:label="@string/superuser_permissions_name"
            android:description="@string/superuser_permissions_description"
            android:protectionLevel="dangerous" />
    
                android:debuggable="true">
           
               
                   
                   
               
           
                        android:label="Superuser" android:permission="android.permission.ACCESS_SUPERUSER">
               
                   
                   
               
           
       
    
    
    
    Launch code is:
    Intent intent = new Intent("android.intent.action.superuser");
    startActivityForResult(intent, SUPERUSER_REQUEST);
    
14. [Issue] How to close current Activity and remove it from Activity history stack when you switch to other Activity
    [Solution] Call "finish()" in current Activity's methods.
15. [Issue] How to use class "Cursor"
    [Solution] Cursor stores the results of database query, such as ContentResolver.query(xxxxx), Cursor contains M(Rows) x N (Columns) eluments, each column has its name and value, we can get them by calling getColumnName() and getString/getInt()/getLong()/getShort()..... etc respectively.
16. [Issue] How to send Http request
    [Solution] Use folloing code:
    (refer to
    http://blog.atrexis.com/index.cfm/2008/6/20/Sending-HTTP-requests-in-Android
    
    http://dev.shufou.com/?p=28
    )
    
        URL url = new URL("");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setDoInput(true);
        conn.setConnectTimeout(10000);
        conn.setRequestMethod(HttpURLConnection.GET);
        conn.setRequestProperty("accept", "*/*");
        String location = conn.getRequestProperty("location");
        int resCode = conn.getResponseCode();
        InputStream stream = conn.getInputStream();
    
17. [Issue] Java Network exception
    - When establish network connection using socket, SocketException is throwed, and exception readable string is: "java.net.SocketException:Connection reset".
    Solution: add android.permission.INTERNET to application manifest
    - Android java.net.SocketException: The connection was reset
    Reason: The time out value is too long, try 10 seconds.
    
18. [Issue] How to communicate in between threads
    [Solution] Use classes Handler & Runnable & Thread
    1) Handler: Provide a type of message process policy, each Handler instance is bound to a single thread and that thread's message queue. A Handler instance just like HWnd of Microsoft Windows, but different from Windows, both Message and the specified object -- Runnable can be send to destination thread's message queue. If Message will be send, Handler must be extended to overload member function handleMessage(Message); If Runnable will be send, Runnable must be extended to overload member function run().
    2) Runnable: Just declare a uniform interface.
    3) Thread: A Thread is a unit of concurrent execution. Througn Thread, we can avoid performing long-running operations directly in the UI thread — the main thread of an application where the UI is run — or your application may be blocked and become unresponsive
    4) Sample:
    public class MyActivity extends Activity
    {
        private Handler m_handler;
        private TextView m_textView;
    
        class MyHandler extends Handler
        {
            public void handleMessage()
            {
                //Flash UI
                m_textView.setText("xxxx");
            }
        }
    
        class MyThread extends Thread
        {
            public void run()
            {
                Message msg = handler.obtainMessage();
                msg.what = xxx;
                msg.obj = xxx;
                msg.sentToTarget();
            }
        }
       
        public void onDestroy()
        {
            super.onDestroy();
            m_handler =  null;
            m_textView = null;
        }
    
        public void onCreate(xxx)
        {
            ......
            m_textView.findViewById(...);
            m_handler = new MyHandler();
            MyThread thread = new MyThread();
            thread.start();
        }
    }
    
19. [Issue] How to uninstall package programmatically
    [Sulotion]
    Uri uri = Uri.fromParts("package", strPackageName, null);  //strPackageName  is package name which will be uninstalled
    Intent it = new Intent(Intent.ACTION_DELETE, uri);
    startActivity(it);
    
    Notes: must request to use permission "android.permission.DELETE_PACKAGES""
    
20. Kill Process
    
    • [Issue] How to terminate process
      [Solution] Use following statement to kill current process:
      android.os.Process.killProcess(android.os.Process.myPid());
      or
      System.exit(-1);
    • How to know application is restarted (killed and launched again)
      You can check in Activity.onCreate
      public void onCreate(Bundle savedInstanceState)
      {
          super.onCreate(savedInstanceState);
      
          final String PREF_FILE = "cfg";
          final String PREF_PREV_PID = "prevPid";
          SharedPreferences pref = getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE);
          if (savedInstanceState == null)
          {
              pref.edit().putInt(PREF_PREV_PID, android.os.Process.myPid()).commit();
          }
          else
          {
              int curPid, prevPid;
              curPid = android.os.Process.myPid();
              prevPid = pref.getInt(PREF_PREV_PID, 0);
              if (prePid == 0 || curPid == prevPid)
              {
                  //Is not killed, maybe activity is restarted after configuration changed
              }
              else
              {
                  //Restarted after killed, by SIGTERM, SIGKILL, or after crashed
              }
          }
      }
      
    • App is killed with SIGTERM or SIGKILL
      When you restart the app from Program list, the previous top activity will be created and shown, the parameter of interface onCreate is not null then.
      If you want to auto launch app once it is killed, just define a service, and implement onStartCommand as following, and start the service when app is launched with interface 'startService(Intent intent)'.
      public int onStartCommand(Intent intent, int flags, int startId)
      {
          if (intent == null) //intent == null means the service is restarted after killed, if it is started with startService in your code, intent != null
          {
              //Launch app here
              stopSelf();
          }
       
          return 1;  //If you don't want Android system to restart the app after it is killed, just return 2;
      }
    • xxx
      
21. [Issue] How to execute P/V operation (mutex, synchronize)
    [Soluction] Use class ConditionVariable or Semaphore
    
22. Atomic (Thread-safe) programming
    
    • AtomicBoolean
    • AtomicInteger
    • AtomicLong
    • AtomicReference
    • AtomicIntegerArray
    • AtomicLongArray
    • AtomicReferenceArray
23. Request to use necessary permission
    If necessary permission is not requested in AndroidManifest.xml, when application is running, it will abort with messages "Source not found" in DEBUG mode, or abort with messages "The application xxx has stopped unexpectedly. Please try again" in RELEASE mode.
    
24. [Issue] How to Get Android package information in Activity
    The Android package information contains all contents defined in AndroidManifest.xml, Such as versionName, versionCode, activities, services, providers, services, signatures etc.
    PackageInfo pkgInfo = getPackageManager().getPackageInfo(getPackageName(), flags);//flags is different for different package information
    i.e. get versionName
    PackageInfo pkgInfo = getPackageManager().getPackageInfo(getPackageName(), 0);
    String verName = pkgInfo.versionName;
    
    Please refer to following online document to get more details
    
    
    
25. [Issue] How to define language(International) and screen orientation(Portrait/Landscape) dependent resource
    [Solution] Please refer to  http://code.google.com/intl/zh-CN/android/devel/resources-i18n.html
    Language tag: http://code.google.com/apis/adsense/developer/adsense_api_locales.html
    
26. [Issue] Activity gets restarted once screen orientation changed
    [Sulution] Add android:configChanges="keyboardHidden|orientation" to your manifest file, if you don't want Activity to be restarted once other configurations are changed, juse append other proper items to android:configChanges, more details about android:configChanges, please refer to http://developer.android.com/intl/zh-CN/reference/android/R.attr.html#configChanges, then search keywords "configChanges"
27. [Issue] What is deployed after application is installed
    [Solution]
    After application is installed,
    1) .apk will be copied to /data/app
    2) An empty directory with the same name as package name of .apk will be created in /data/data
    3) /data/system/packages.xml will be updated
    (More details, please refer to Android Package Installation http://blog.csdn.net/loughsky/archive/2008/11/14/3298868.aspx )
    
28. Implment schedule task
    Use AlarmManager.
    Sample:
    mgr=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
    Intent i=new Intent(context, OnAlarmReceiver.class);
    PendingIntent pi=PendingIntent.getBroadcast(context, 0, i, 0); //or call getService/getActivity for Service/Activity intent
    
    mgr.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime(), PERIOD, pi);
    In this example, I am using setRepeating(). If you want a one-shot alarm, you would just use set(). Be sure to give the time for the alarm to start in the same time base as you use in the initial parameter to set(). In my example above, I am using AlarmManager.ELAPSED_REALTIME_WAKEUP, so my time base is SystemClock.elapsedRealtime().
    
29. Get packages information
    Use PackageManager.
    Use PackageManager.getPackageManager to get package manager instance.
    The installation file name is PackageManager.getPackageManager.applicationInfo.sourceDir
    
    
30. List all media files
    i.e.:
    Uri[] uriMedia = {
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            MediaStore.Images.Media.INTERNAL_CONTENT_URI,
            MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
            MediaStore.Audio.Media.INTERNAL_CONTENT_URI,
            MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
            MediaStore.Video.Media.INTERNAL_CONTENT_URI
        };
    for (int i = 0; i < uriMedia.length; i++)
    {
        Cursor cur = resolver.query (uriMedia[i], null, null, null, null);
        while (cur.moveToNext())
        {
            String strFileName = cur.getString(cur.getColumnIndexOrThrow(MediaStore.MediaColumns.DATA));
    //All supported cursor columns are MediaStore.MediaColumns, MediaStore.MediaColumns, MediaStore.Audio.AudioColumns, MediaStore.Video.ViceoColumns, MediaStore.Images.ImagesColumns
        }
    }
                 
    Sample:
    
31. Add scroll bar
    Add ScrollView out of target view, i.e
    
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        >
    
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />
    
            android:id="@+id/headertable"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:stretchColumns="1"
            android:collapseColumns="2"/>
    android:layout_width="fill_parent"
            android:layout_height="wrap_content">
    >
    
    Issue: if scroll bar overwrap contents within the scrollview, you can add android:scrollbarStype="insideInset" to ScrollView, i.e.
    
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:scrollbarStype="insideInset"
        >
    or set dynamic in source code as:
    findViewById(R.id.scroll_view_id).setScrollBarStyle(View.SCROLLBARS_INSIDE_INSET);
    
32. Can't get phone number use TelephonyManger
1.  Verify proper permissions is declared in manifest file
   
2.  Check whether getLine1Number() returns null ?
3. Verify the setting application (go to Settings > About phone > Status > (My) phone number). You should be able to see your phone number.
4. In cases where you have the radio switched off you cannot read the
   phone number from your SIM card or the SIM card is not available at all, for example, the phone network is switch to Airplane mode.
   
5. ...
   
33. Get subscriber id
1. Verify proper permissions is declared in manifest file
2. The phone network is available.
3. You can access the website and input the IMSI to verify:
   
   
4. ...
   
34. How to know which table is created in datebase, and what columns the table contains.
    i.e. Get to know table details in /data/data/com.google.providers.telephony/databases/mmssms.db.
    Solution:
    1, adb pull /data/data/com.google.providers.telephony/databases/mmssms.db .
    2, strings mmssms.db  > tmp.txt
    3, vi tmp.txt, and search 'CREATE TABLE'
    
35. Backward Compatibility for Application
    http://developer.android.com/resources/articles/backward-compatibility.html
    
36. Input Methods
    http://developer.android.com/resources/articles/creating-input-method.html
    
37. Relayout UI
    
    • Change Layout Attributes
      RelativeLayout layout = (RelativeLayout) findViewById(R.id.xxxx);
      RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams)layout.gerLayoutParams();
      params.addRules(xxx, xxx);
      layout.addLayoutParams(params);
      layout.requestLayout();
    • Dynamic Add/Remove SubViews
      Layout layout = (Layout)findViewById(xxxx);
      layout.removeAllViews();     or
      layout.removeViewAt(xxx);    or
      layout.removeView(xxx);
      ....
      layout.addView(xxx); or
      layout.addViewAt(xxx);
      
      ================================
      or View view = fineViewById(xxxx);
      view.setVisible(View.GONE);
      
      The layout will relayout and align automatically.
      
38. Change button's image
    call setCompondDrawablesWithIntrinsicBounds
    
39. The title of TableHost can't be shown (it background's color is the same as foreground's)
    It may caused by sdb version. that is you build application with higher Android SDK, but in AndroidManifest file, you specified lower SDK version using
    
40. Launch an Activity from background to foreground
    you can't switch your activity from background to foreground in Activity, you must do this in Service.
    1st Way:
    Intent intent = new Intent(parentIntnet, target.class);
    intent.setAction(xxxx);
    intent.addCategory(xxx);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED)
    startActivity(intent);
    
    2nd way:
    Intent intent = new Intent(this, TergatActivity.class)
    intent.setFlags(Intnet.FLAG_ACTIVITY_NEW_TASK);
    getApplicationContext().startActivity(intent);  //Must set flags Intnet.FLAG_ACTIVITY_NEW_TASK to intent;
    
    
41. Activity is restarted automatically
    In following situations, Activity will be restarted automatically.
    
    • Memory is low
      Override onLowMemory method to see if it is called before Activity is restarted. If this method is called, your application uses too much memory.
      
      In such situation, you must optimize your application to decrease low memory usage.
      
    • Configuration is changed
      
      • in AndroidManifest.xml, add android:configChanges attributes in Activity elements, and set it to all available value (About available value, please refer to http://developer.android.com/guide/topics/manifest/activity-element.html ), ie. android:configChanges="mcc|mnc|locale|touchscreen|keyboard|keyboardHidden|navigation|orientation|screenLayout|fontScale"
      • Override  method onConfigurationChanged(Configuration newConfig) to see if it is called. If it is called, it is configuration changing to cause your Activity restarted.
        
      
      In such situlation, you can set proper android:configChanges (First, add all available value to android:configChanges, then decrease it from android:configChanges one by one) to prevent your Activity to be restarted.
      
42. How to use Android internal package
    such as com.android.internal.*
    [Solution]
    Get source code of internal package and depended packages, then add the source code to you project.
    [ie] To use internal class ITelephony
    
    • Prepare ITelephony.aidl
      Download iTelephony.aidl from
      then add that file to src/com/android/internal/telephony/ of your project
    • Write code
      import com.android.internal.telephony.ITelephony;
      ......
      ITelephony telephonyService = ITelephony.Stub.asInterface(ServiceManager.getService(Context.TELEPHONE_SERVICE);
      
      //Call method of ITelephony
      telephonyService.endCall();
      
    • xxx
      
    
    
43. When to start an activity via method startActivityForResult, don't set flag FLAG_ACTIVITY_NEW_TASK
    
44. DateFormat
    DateFormat can be found in packages java.text and android.text.format. If you want to refer to the user configured date format, you need to use the class DateFormat in the package android.text.format by invoking the metohd getDateFormat(context);
    
45. Get locale
    Use Locale class
    
46. The ways to monitor process is created
    
    • Use i-notifi (FileObserver) to monitor /proc/loadavg
    • Run logcat and parse output log records
      try
      {
          String line;
          Process p = Runtime.getRuntime().exec("logcat");
          BufferedReader input = new BufferedReader (new InputStreamReader(p.getInputStream()));
          while ((line = input.readLine()) != null) //If no data is available, this function will hang until the process is terminated.
          {
              System.out.println(line);
          }
          input.close();
      }
      catch (Exception err)
      {
          err.printStackTrace();
      }
      
    • xxx
      
47. The difference between padding and margin
    The padding space is belong of the View, while the space of margin is not. Padding means set extra space from contensts, while margin means add extra space from UI component.
    
48. Color
    Many color is pre-defined, such as Color.RED, Color.GREEN, Color.BLUE etc.
    
49. How to process un-catched exception yourself
    Refer to http://blogold.chinaunix.net/u/9577/showart_2323574.html
    
50. ...
    
2. Debug
1. adb
1. Open shell of mobile device from host
   Run "adb shell" on terminal on your host computer which is connected to your mobile device.
   
2. Get system log
   Run "adb logcat" on terminal on your host computer which is connected to your mobile device, then system logs generated on mobile device sill display on the terminal.
   
3. ,,,
   
2. Debug on device
   - Set build mode to "Debug" on Eclipse before build
   - Select the checkbox "Settings->Applications->Unknown sources" on mobile device
   - Select the checkbox "Settings->Applications->Development->USB debugging" on mobile device
   
3. Set USB Mode
   - Drag status bar to open prompt
   - Press USB Connection to select mode
   
4. StrictMode
   StrictMode is a developer tool which detects things:
• Detect when an Closeable or other object with a explict termination method is finalized without having been closed.
• Detect when an SQLiteCursor or other SQLite object is finalized without having been closed.
• Enable detection of disk reads.
• Enable detection of disk writes.
• Enable detection of network operations.
• ......
  
5. [Issue] How to list all GUI objects
   [Solution]
   Make sure you have a dev device/emulator (if you see "1", you're out of luck):
   $ adb shell getprop ro.secure
   0
   
   Start the server:
   $ adb shell service call window 1 i32 4939
   
   You should see the following result (the "1" means the server is running):
   Result: Parcel(00000000 00000001   '........')
   
   Install the port forwarding:
   $ adb forward tcp:4939 tcp:4939
   
   Connect to the server:
   $ telnet localhost 4939
   
   Now, you can use one of two commands (type enter after each command):
   
   - LIST will show the list of windows:
   LIST
   43514758 com.android.launcher/com.android.launcher.Launcher
   4359e4d0 TrackingView
   435b00a0 StatusBarExpanded
   43463710 StatusBar
   43484c58 Keyguard
   DONE.
   
   - DUMP will show the views and their properties for a given window.
   For instance, DUMP 43514758 will show the views contained in the
   window com.android.launcher/com.android.launcher.Launcher. You can
   also use DUMP -1 or DUMP ffffffff to dump the foreground window. I
   recommend that version. The dump may take a while go be generated and
   it looks like this:
   
   DUMP -1
   com.android.internal.policy.impl.KeyguardViewManager$KeyguardViewHost@434d8220
   getDescendantFocusability()=24,FOCUS_BEFORE_DESCENDANTS
   getPersistentDrawingCache()=9,SCROLLING
   isAlwaysDrawnWithCacheEnabled()=4,true
   isAnimationCacheEnabled()=4,true
   isChildrenDrawnWithCacheEnabled()=5,false mMinWidth=1,0 mMinHeight=1,0
   mMeasuredWidth=3,320 mMeasuredHeight=3,455 mPaddingBottom=1,0
   mPaddingLeft=1,0 mPaddingRight=1,0 mPaddingTop=1,0 mLeft=1,0
   mID=5,NO_ID mPrivateFlags=4,3248 mRight=3,320 mScrollX=1,0
   mScrollY=1,0 mBottom=3,455 mTop=1,0 mUserPaddingBottom=1,0
   mUserPaddingRight=1,0 mViewFlags=9,402653312 getBaseline()=2,-1
   getHeight()=3,455 layout_height=11,FILL_PARENT
   layout_width=11,FILL_PARENT getTag()=4,null getVisibility()=7,VISIBLE
   getWidth()=3,320 hasFocus()=4,true isClickable()=5,false
   isDrawingCacheEnabled()=5,false isEnabled()=4,true
   isFocusable()=5,false isFocusableInTouchMode()=5,false
   isFocused()=5,false isHapticFeedbackEnabled()=4,true
   isInTouchMode()=4,true isSelected()=5,false
   isSoundEffectsEnabled()=4,true willNotCacheDrawing()=5,false
   willNotDraw()=4,true
   ...
   DONE.
   
   The format is simple. Each View is defined on a line of text which
   ends with \n. The indent at the beginning of the line indicates the
   depth of the child in the hierarchy. For instance, no indent == root,
   1 space == child of the root, 2 spaces == child of a child of the
   root, etc.
   
   className@id followed by a list of properties. A property has the
   following format: name=X,data where X is the number of characters in
   the data.
   
6. Useful debug tools
1. am
   Log into the shell of mobile device, then type the following command on shell:
   - Run application:
       $am start -n /.
   - Enter debug mode when run app, just add -D before -n, i.e.
       $am start -D -n com.mydomain.test/com.mydomain.test.Main
   - Trigger broadcast
       am start -a
       i.e.:
       am start -a android.intent.action.MEDIA_BUTTON
   
2. ...
   
7. [Issue] When you compile your project, following error message is shown
   invalid resource directory name
   The project cannot be built until build path errors are resolved
   [Solution] Invalid file may exist under directory 'res/' and/or its sub-directory. For example, a .txt file exists in the directory res/. Just find the invalid file then remove it.
   
8. When to launch activity, the following error occurs:
   Java.lang.SecurityException: permission Denial: Starting intent {flg=xxx cmp=xxxx xxxx} for null (pid=xxx uid=xxx) requires null
   [Reason]In eclair, the CropImage activity has no intent-filter associated with it, so it is not exported.  This means it cannot be launched by components of other applications.  If this is what you are trying to do, then that would explain the failure.
   [Solution]
   1st way: add android:exported="true" to all activity/service/receiver
   2nd way: Add intent-filter to all activity/service/receiver, such as
   
   
   
   
9. ...
   
3. SDKs Issue
1. [Issue] SDK 1.5 build error
   [2009-07-01 15:13:50 - HelloWorld] no classfiles specified
   [2009-07-01 15:13:50 - HelloWorld] Conversion to Dalvik format failed with error 1
   [Solution]:
    Step 1: Right click->project -> properties -> android -> project build target to set target to SDK 1.5
    Step 2: Click Project, then press F5 to reload project files.
2. [Issue] SDK 2.1 no available targets
   [Solution] On Eclipse, click Window -> Android SDK and AVD Manager -> Installed Packages -> Update All, (Or click Window -> Android SDK and AVD Manager -> Available Packages to install necessory sdk first.)
   
3. [Issue] Build error: Project XXX is missing required source folder: 'gen'。
   [Solution] Remove R.java, then flash project, and build again.
   
4. [Issue] Create AVD (Android Virtual Devices) for Eclipse
   [Solution] click Window -> Android SDK and AVD Manager -> Ivirtual Devices,
   
5. Error sulition when to install ADT
   
   
   for eclipse 3.5
   Use Window > Preferences > Install/Update > Available Software Sites to add the following
   
   
   
   
6. ......
   
4. NDK Issue
1. [Issue] Install NDK error
   When install NDK with command:
    $ ./build/host-setup.sh
   Following error message display:
   Detecting host toolchain.
   ./host-setup.sh: 57: force_32bit_binaries: not found
   ./host-setup.sh: 58: setup_toolchain: not found
   ./host-setup.sh: 60: cannot create : Directory nonexistent
   Can't create directory for host config file: out/host
   [Solution]
    $ cd /bin
    $ rm sh
    $ ln -s bash sh
   or change the first line of file ./build/host-setup.sh to "#!/bin/bash"
   
5. Enulator
1. [Issue] How to switch screen orientation
   [Solution] Ctrl + F11
2. ...
   
6. Android Phone Using
1. [Issue] While mobile device is connected to host pc, the popup windows can't get response on host pc
   [Solution] just kill process f-spot.exe on host pc
   
2. [Issue] How to login into mobile device with telnet
   [Solution]
   1) Reboot device
   2) Open terminal
   3) run 'cd /; cd system; cd bin; telnet' on device
   4) telnet on remove computer.
   
3. ...
   
7. Build with Eclipse
1. [Issue] When build application,following error message display
   ERROR: Application does not specify a android.test.InstrumentationTestRunner instrumentation or does not declare uses-library android.test.runner
   [Solution 1]
    - Add following code to AndroidManifest.
              android:targetPackage="your.package"
             android:label="your tests label" />
   
   
   - Right click project on Project Explorer Panel on Eclipse, then click "Run" > "Run Configurations...", then select "android.test.InstrumentationTestRunner" in Instrumentation TestRunner.
   [Solution 2]
   When to run application via Eclipse, don't select "xxx JUnit Test" on "Run As" dialog. Or right click project on Project Explorer Panel on Eclipse, then create a new Run/Debug configure file under the  categories except "xxx JUint Test"
   
2. ...
   
   
8. Sign package
1. keytool error
   [Issue]
   c:\3960\glassfish\domains\domain1\config>keytool -genkey -keyalg RSA -keystore a
   mkeystore.jks -validity 365 -alias "fam8" -dname "amqa-x2100-01.red.iplanet.com,
   ou=identity,o=sun.com,L=santa clara, ST=CA, C=US"
   Enter keystore password:
   Re-enter new password:
   keytool error: java.io.IOException: Incorrect AVA format
   
   [Solution]
   dname format is wrong, it shold be
   Should be "cn=amqa-x2100-01.red.iplanet.co..........."
   
2. ...
   
9. Sign Application
1. Manual of keytool
   
   
10. How to access Android resource
    with android.R.xxx, i.e. android.R.string.xxx, android.R.drawable.xxx
    
11. App stores
    
    • SK Telecom store (TStore)
      
      
12. Publish & Market
    
    • Tutorial
      http://developer.android.com/guide/index.html (Search publish)
      
    • Publish
      
      
    • Support
      
    • Update process:
      (Refer to:)
      - Tap on the Notification menu at the top and drag it down.
      - If there are application updates, they will be displayed.
      - Just tap on that item and you'll be taken into the Android Market and be presented with a list of all installed programs that have an update.
      - Tap on the application to begin the update.
      - Next, tap Update. The program will remind you it's replacing the current version. Tap OK.
      - Now you'll be shown all the things the application has access to. Tap OK.
      - Your application will be installed and you'll be up to date.
      - Repeat this process for your other applications.
      
    • Delete published application
      (Refer to: )
      Go to the developers console, click on your application to display and edit it's details, and there is an un-publish option.
      
      
      Your application will no longer be listed in The Market application, and  non one will be able to install copies of it.
      Anyone who already has your application installed will continue to have it on their phones. If they uninstall it they will not be able to get it back.
      
      
    • xxx
      
13. Run
    [Q]Unable to execute dex: wrapper was not properly loaded first
    [A]找到Eclipse目录下eclipse.ini文件，将最后两句改为
    -Xms128m
    -Xmx512m
    重启eclipse
    然后project->clean一下就OK了
14. ...