android 优化

1.图像缩放

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private void compressImage(String pathName) {         BitmapFactory.Options options = new BitmapFactory.Options();         options.inSampleSize = 10; // 为原来图形的1/10         Bitmap bitmap  = BitmapFactory.decodeFile(pathName ,options);         // 显示图像到控件         ImageView imageView = new ImageView(getApplicationContext());         imageView.setImageBitmap(bitmap);         bitmap.recycle();     }

2.及时释放对象

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class ImageManager{     //实现统一管理位图资源     private WeakHashMap<Integer, WeakReference<Bitmap>> mBitmaps;     private WeakHashMap<Integer, WeakReference<Drawable>> mDrawable;     private boolean mActive = true;     public ImageManager(){         mBitmaps = new WeakHashMap<Integer, WeakReference<Bitmap>>();         mDrawable = new WeakHashMap<Integer, WeakReference<Drawable>>();     }     public  Bitmap  getmBitmaps(int resource) {         if (mActive) {             if (!mBitmaps.containsKey(resource)) {                 mBitmaps.put(resource, new WeakReference<Bitmap>(BitmapFactory.decodeResource(getResources(), resource)));                 return ((WeakReference<Bitmap>)mBitmaps.get(resource)).get();             }         }         return  null;     }       public Drawable getDrawable(int resource){         if (mActive) {             if (!mDrawable.containsKey(resource)) {                 mDrawable.put(resource, new WeakReference<Drawable>(getResources().getDrawable(resource)));                 return ((WeakReference<Drawable>)mDrawable.get(resource)).get();             }         }           return null;     }     public void recycleBitmaps(){         Iterator iterator = mBitmaps.entrySet().iterator();         while (iterator.hasNext()) {             Map.Entry type = (Map.Entry) iterator.next();             ((WeakReference<Bitmap>)type.getValue()).get().recycle();           }     }     private ImageManager setActive(boolean b) {         // TODO Auto-generated method stub         mActive = b;         return this;       }     public boolean isActive(){         return mActive;     } }

3.

哟话网络连接, 

首先检测网络是否正常, 如没有网络就不执行相应的程序, 

检查网络连接的演示代码如下:

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public boolean isConnected(){         ConnectivityManager manager  = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);         TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);         NetworkInfo info = manager.getActiveNetworkInfo();         if (info==null||!manager.getBackgroundDataSetting()) {// 无可用网络连接             return false;         }         //网络类型判断, 只有3G或者wifi里进行数据更新         int netType = info.getType();         int netsubType = info.getSubtype();         if (netType == ConnectivityManager.TYPE_WIFI) {             return info.isConnected();         }         else if (netType == ConnectivityManager.TYPE_MOBILE&&netsubType == TelephonyManager.NETWORK_TYPE_UMTS&&!telephonyManager.isNetworkRoaming()){             return info.isConnected();         }else{             return false;         }     }

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