1、展开、收起状态栏
public static final void collapseStatusBar(Context ctx) { Object sbservice = ctx.getSystemService("statusbar"); try { Class<?> statusBarManager = Class.forName("android.app.StatusBarManager"); Method collapse; if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) { collapse = statusBarManager.getMethod("collapsePanels"); } else { collapse = statusBarManager.getMethod("collapse"); } collapse.invoke(sbservice); } catch (Exception e) { e.printStackTrace(); } } public static final void expandStatusBar(Context ctx) { Object sbservice = ctx.getSystemService("statusbar"); try { Class<?> statusBarManager = Class.forName("android.app.StatusBarManager"); Method expand; if (Build.VERSION.SDK_INT >= 17) { expand = statusBarManager.getMethod("expandNotificationsPanel"); } else { expand = statusBarManager.getMethod("expand"); } expand.invoke(sbservice); } catch (Exception e) { e.printStackTrace(); } }
用途：可用于点击Notifacation之后收起状态栏
2、 获取状态栏高度
public static int getStatusBarHeight(Context context){ Class<?> c = null; Object obj = null; Field field = null; int x = 0, statusBarHeight = 0; try { c = Class.forName("com.android.internal.R$dimen"); obj = c.newInstance(); field = c.getField("status_bar_height"); x = Integer.parseInt(field.get(obj).toString()); statusBarHeight = context.getResources().getDimensionPixelSize(x); } catch (Exception e1) { e1.printStackTrace(); } return statusBarHeight; }
3、ListView使用ViewHolder极简写法
public static <T extends View> T getAdapterView(View convertView, int id) { SparseArray<View> viewHolder = (SparseArray<View>) convertView.getTag(); if (viewHolder == null) { viewHolder = new SparseArray<View>(); convertView.setTag(viewHolder); } View childView = viewHolder.get(id); if (childView == null) { childView = convertView.findViewById(id); viewHolder.put(id, childView); } return (T) childView; }
用法：
@Override public View getView(int position, View convertView, ViewGroup parent) { if (convertView == null) { convertView = LayoutInflater.from(getActivity()).inflate(R.layout.fragment_feed_item, parent, false); } ImageView thumnailView = getAdapterView(convertView, R.id.video_thumbnail); ImageView avatarView = getAdapterView(convertView, R.id.user_avatar); ImageView appIconView = getAdapterView(convertView, R.id.app_icon);
用起来非常简练，将ViewHolder隐于无形。
4、 设置Activity透明
<style name="TransparentActivity" parent="AppBaseTheme"> <item name="android:windowBackground">@android:color/transparent</item> <item name="android:colorBackgroundCacheHint">@null</item> <item name="android:windowIsTranslucent">true</item> <item name="android:windowNoTitle">true</item> <item name="android:windowContentOverlay">@null</item> </style>
说明：AppBaseTheme一般是你application指定的android:theme是啥这里就是啥，否则Activity内部的空间风格可能不一致。
用途：用于模拟Dialog效果，比如再Service中没法用Dialog，就可以用Activity来模拟
5、 代码切换全屏
//切换到全屏 getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN); getActivity().getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); //切换到非全屏 getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); getWindow().addFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
注意：切换到全屏时，底部的虚拟按键仍然是显示的。次方法可多次调用用于切换
用途：播放器界面经常会用到
6、调用开发者选项中显示触摸位置功能
android.provider.Settings.System.putInt(getContentResolver(), "show_touches", 1);
设置1显示，设置0不显示。
7、获取设备上已安装并且可启动的应用列表
Intent intent = new Intent(Intent.ACTION_MAIN); intent.addCategory(Intent.CATEGORY_LAUNCHER); List<ResolveInfo> activities = getPackageManager().queryIntentActivities(intent, 0)
注意：使用getInstalledApplications会返回很多无法启动甚至没有图标的系统应用。ResolveInfo.activityInfo.applicationInfo也能取到你想要的数据。
