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Android_CodeWiki_04

时间:2015-02-01 21:45:30      阅读:174      评论:0      收藏:0      [点我收藏+]

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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。

 

Android_CodeWiki_04

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原文地址:http://www.cnblogs.com/spring87/p/4266130.html

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