android一些技巧

        
        EditText ed = new EditText(this);
        Editable eb = ed.getEditableText();

        //获取光标位置
        int position = ed.getSelectionStart();

        //指定位置插入字符
        eb.insert(position, "XXX");


        //插入图片
        //定义图片所占字节数（“Tag”的长度）
        SpannableString ss = new SpannableString("Tag");
        //定义插入图片
        Drawable drawable = getResources().getDrawable(R.drawable.icon);
        ss.setSpan(new ImageSpan(drawable,ImageSpan.ALIGN_BASELINE), 0, ss.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        drawable.setBounds(2, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
        //插入图片
        eb.insert(position, ss);


        //设置可输入最大字节数
        ed.setFilters(new InputFilter[]{new InputFilter.LengthFilter(10)});


        //拉起lancher桌面
        Intent i = new Intent(Inten.ACTION_MAIN);
       i.addCategory(Inten.CATEGORT_HOME);
       startActivity(i);

       //去掉List拖动时的阴影
        list.setCacheColorHint(0);      
       
      // 通过资源名称获取资源id 
        1.Field f= (Field)R.drawable.class.getDeclaredField("Name");
        int id=f.getInt(R.drawable.class);
     2.int id = getResources().getIdentifier(getPackageName()+":drawable/Name", null,null);
       // timer TimerTask用法
        mTimer = new Timer();
        mTimerTask = new TimerTask() {
			@Override
			public void run() {
				mProgress.setProgress(mMediaPlayer.getCurrentPosition());
				mHandler.sendEmptyMessage(0);
			}
		};
		mTimer.schedule(mTimerTask, 0, 1000);
        // 在a.apk启动b.apk的实现
         //1.a.apk实现
	Intent mIntent = new Intent("package.MainActivity"); 
	startActivity(mIntent);
	finish(); 
        // b.apk在mainfest中配置
            <intent-filter>
                <action android:name="package.MainActivity" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
//Android 获取存储卡路径和空间使用情况
       /** 获取存储卡路径 */ 
File sdcardDir=Environment.getExternalStorageDirectory(); 
/** StatFs 看文件系统空间使用情况 */ 
StatFs statFs=new StatFs(sdcardDir.getPath()); 
/** Block 的 size*/ 
Long blockSize=statFs.getBlockSize(); 
/** 总 Block 数量 */ 
Long totalBlocks=statFs.getBlockCount(); 
/** 已使用的 Block 数量 */ 
Long availableBlocks=statFs.getAvailableBlocks(); 


//Android 为Activity屏幕的标题添加图标
Window win = getWindow();
　　win.requestFeature(Window.FEATURE_LEFT_ICON);
　　setContentView(R.layout.mylayout);
　　win.setFeatureDrawableResource(Window.FEATURE_LEFT_ICON, R.drawable.icon);
//图片缩放
1.ThumbnailUtils.extractThumbnail(bitmap,200,100)
2.  //使用Bitmap加Matrix来缩放   
     public static Drawable resizeImage(Bitmap bitmap, int w, int h)   
     {    
        Bitmap BitmapOrg = bitmap;    
         int width = BitmapOrg.getWidth();    
         int height = BitmapOrg.getHeight();    
         int newWidth = w;    
         int newHeight = h;    
   
         float scaleWidth = ((float) newWidth) / width;    
         float scaleHeight = ((float) newHeight) / height;    
   
         Matrix matrix = new Matrix();    
         matrix.postScale(scaleWidth, scaleHeight);    
         // if you want to rotate the Bitmap      
         // matrix.postRotate(45);      
         Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width,    
                         height, matrix, true);    
         return new BitmapDrawable(resizedBitmap);    
     }  
3. //使用BitmapFactory.Options的inSampleSize参数来缩放   
     public static Drawable resizeImage2(String path,  
             int width,int height)   
     {  
         BitmapFactory.Options options = new BitmapFactory.Options();  
         options.inJustDecodeBounds = true;//不加载bitmap到内存中   
         BitmapFactory.decodeFile(path,options);   
         int outWidth = options.outWidth;  
         int outHeight = options.outHeight;  
         options.inDither = false;  
         options.inPreferredConfig = Bitmap.Config.ARGB_8888;  
         options.inSampleSize = 1;  
           
         if (outWidth != 0 && outHeight != 0 && width != 0 && height != 0)   
         {  
             int sampleSize=(outWidth/width+outHeight/height)/2;  
             Log.d(tag, "sampleSize = " + sampleSize);  
             options.inSampleSize = sampleSize;  
         }  
       
        options.inJustDecodeBounds = false;  
         return new BitmapDrawable(BitmapFactory.decodeFile(path, options));       
     }