android琐碎记四

1. 横屏的一种简单方法 只能横屏不能竖屏
<activity android:name=".SomeActivity"            
android:label="@string/app_name"             
android:screenOrientation="portrait">

2.SaveInstanceState的使用
@Override
public void onSaveInstanceState(Bundle savedInstanceState) { 
  // Save UI state changes to the savedInstanceState. 
  // This bundle will be passed to onCreate if the process is 
  // killed and restarted. 
  savedInstanceState.putBoolean("MyBoolean", true); 
  savedInstanceState.putDouble("myDouble", 1.9); 
  savedInstanceState.putInt("MyInt", 1); 
  savedInstanceState.putString("MyString", "Welcome back to Android"); 
  // etc. 
  super.onSaveInstanceState(savedInstanceState);
  }

@Override
  public void onRestoreInstanceState(Bundle savedInstanceState) { 
  super.onRestoreInstanceState(savedInstanceState); 
  // Restore UI state from the savedInstanceState. 
  // This bundle has also been passed to onCreate. 
  boolean myBoolean = savedInstanceState.getBoolean("MyBoolean"); 
  double myDouble = savedInstanceState.getDouble("myDouble"); 
  int myInt = savedInstanceState.getInt("MyInt"); 
  String myString = savedInstanceState.getString("MyString");
  }

3.让editText不能用
editText.setFocusable(false);和editText.setEnabled(false);
只能使背景不同但是还是能输入进去能去，下面的办法是：
editText.setFilters(new InputFilter[] {   
     new InputFilter() {       
          public CharSequence filter(CharSequence src, int start,  int end, Spanned dst, int dstart, int dend) {               
          return src.length() < 1 ? dst.subSequence(dstart, dend) : "";       
          }   
          }
          });

4.连接网络下载图片简单代码：不要忘记放在线程里面或者AsyncTask 里面执行
http://developer.android.com/reference/android/os/AsyncTask.html：
private Bitmap fetchImage( String urlstr ){   
             try    {       
                     URL url;      
                      url = new URL( urlstr );       
                      HttpURLConnection c = ( HttpURLConnection ) url.openConnection();       
                      c.setDoInput( true );       
                      c.connect();      
                       InputStream is = c.getInputStream();      
                        Bitmap img;       
                        img = BitmapFactory.decodeStream( is );       
                        return img;    }   
                        catch ( MalformedURLException e )    {      
                         Log.d( "RemoteImageHandler", "fetchImage passed invalid URL: " + urlstr );   
                         }   
                         catch ( IOException e )    {       
                         Log.d( "RemoteImageHandler", "fetchImage IO exception: " + e );  
                          }   
                          return null;
                          }
5. 可以用来远端更新安装程序部分代码：
DexFile df = new DexFile(new File("/data/app/my_downloaded_lib.apk"));
                          ClassLoader cl = getClassLoader();
                          Class clazz = df.loadClass("com/my/lib/MyClass", cl);

6.调用选择时间加减的方框 注意不是timepiker :
<com.android.internal.widget.NumberPicker    android:id="@+id/picker"    android:layout_width="wrap_content"    android:layout_height="wrap_content"/>

Object o = findViewById(R.id.picker);
  Class c = o.getClass();
  try {   
     Method m = c.getMethod("setRange", int.class, int.class);   
     m.invoke(o, 0, 9);}
     catch (Exception e) {   
     Log.e("", e.getMessage());
     }
http://groups.google.com/group/android-developers/browse_frm/thread/65da9820998fddc9/6151cc9800e6a04d?pli=1

7.对话框修改 标题栏的大小
dialog = new Dialog(context);
     Window window = dialog.getWindow();
     window.requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
     dialog.setContentView(R.layout.my_dialog_layout);
     window.setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.my_custom_header);

8.程序更改Android Tab Icons
tabHost.setOnTabChangedListener(new OnTabChangeListener() {               
   public void onTabChanged(String tabId) {                       
     if (TAB_MAP.equals(tabId)) {                               
          ImageView iv = (ImageView)tabHost.getTabWidget().getChildAt(0).findViewById(android.R.id.icon);                               
          iv.setImageDrawable(getResources().getDrawable(R.drawable.tab_map_black));                               
          iv = (ImageView)tabHost.getTabWidget().getChildAt(1).findViewById(android.R.id.icon);                              
           iv.setImageDrawable(getResources().getDrawable(R.drawable.tab_list_white));                      
         }
     else if (TAB_LIST.equals(tabId)) {                               
        ImageView iv = (ImageView)tabHost.getTabWidget().getChildAt(0).findViewById(android.R.id.icon);                               
        iv.setImageDrawable(getResources().getDrawable(R.drawable.tab_map_white));                               
        iv = (ImageView)tabHost.getTabWidget().getChildAt(1).findViewById(android.R.id.icon);                               
        iv.setImageDrawable(getResources().getDrawable(R.drawable.tab_list_black));                      
         }               
         }      
          });