android小知识（2）

1、Android启动外部应用

（1）、根据包名启动

PackageManager manager = getPackageManager();
Intent launchIntentForPackage = manager.getLaunchIntentForPackage("要打开软件的包名");
if (launchIntentForPackage != null) {
    startActivity(launchIntentForPackage);
}

（2）、启动应用的某个界面

Intent intent = new Intent();
intent.addCategory(Intent.CATEGORY_LAUNCHER);
intent.setAction(Intent.ACTION_MAIN);
intent.setComponent(new ComponentName(“包名”, "界面的类名");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);

2、打开软件安装页面

Intent intent = new Intent();
intent.setAction("android.intent.action.VIEW");
intent.addCategory("android.intent.category.DEFAULT");
intent.setDataAndType(Uri.fromFile(new File("apk所在路径")), "application/vnd.android.package-archive");
startActivityForResult(intent, 0);  

3、卸载软件

Intent intent = new Intent();
intent.setAction("android.intent.action.DELETE");
intent.addCategory("android.intent.category.DEFAULT");
intent.setData(Uri.parse("package:" + "卸载的包名"));
startActivityForResult(intent, 0);

4、打开软件详情页

Intent intent = new Intent();
intent.setAction("android.settings.APPLICATION_DETAILS_SETTINGS");
intent.setData(Uri.parse("package:" + "软件包名"));
startActivity(intent);

5、分享内容

Intent intent = new Intent();
intent.setAction("android.intent.action.SEND");
intent.addCategory("android.intent.category.DEFAULT");
intent.setType("text/plain");
intent.putExtra(Intent.EXTRA_TEXT, "分享的内容");
startActivity(intent);

6、动态获取服务是否开启的方法

public static boolean isRunningService(String className,Context context){
    ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    List<RunningServiceInfo> runningServices = activityManager.getRunningServices(300);//300    表示正在运行的服务的上限个数,一般300足够了
    //遍历集合
    for (RunningServiceInfo runningServiceInfo : runningServices) {

        ComponentName service = runningServiceInfo.service;
        //正在运行的服务的全类名
        String className2 = service.getClassName();

        //正在运行的服务的全类名和传递过来的服务的全类名比较,相同正在运行返回true,不相同表示服务没有运行返回false
        if (className.equals(className2)) {
            return true;
        }
    }
    return false;
}

7、获取内存卡可用空间 ##public static long getAvailableROM(){

    //获取内存路径
    File path = Environment.getDataDirectory();
    //硬盘的API操作
    StatFs stat = new StatFs(path.getPath());
    long blockSize = stat.getBlockSize();//获取每块的大小
    long totalBlocks = stat.getBlockCount();//获取总块数
    long availableBlocks = stat.getAvailableBlocks();//获取可用的块数
    return availableBlocks*blockSize;
}

8、获取SD卡可用空间

public static long getAvailableSD(){
    File path = Environment.getExternalStorageDirectory();
    StatFs stat = new StatFs(path.getPath());
    long blockSize = stat.getBlockSize();//每块的大小
    long totalBlocks = stat.getBlockCount();//总块数
    long availableBlocks = stat.getAvailableBlocks();//可用的块数
    return availableBlocks*blockSize;
}

9、获取剩余内存和总内存

public static long getAvailableRam(Context context){
    ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

    MemoryInfo outInfo = new MemoryInfo();
    am.getMemoryInfo(outInfo);
    //空闲的内存
    return outInfo.availMem;
}

public static long getTotalRam(Context context){
    ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

    MemoryInfo outInfo = new MemoryInfo();
    am.getMemoryInfo(outInfo);

    //总的内存
    return outInfo.totalMem;
}

10、获取手机屏幕高度和宽度

WindowManager windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
DisplayMetrics outMetrics = new DisplayMetrics();
windowManager.getDefaultDisplay().getMetrics(outMetrics);
width = outMetrics.widthPixels;
height = outMetrics.heightPixels;

11、判断网络活动状态

public static boolean isNetworkConnected(Context context) {
    if (context != null) {
        ConnectivityManager mConnectivityManager = (ConnectivityManager) context
            .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();
        if (mNetworkInfo != null) {
            return mNetworkInfo.isAvailable();
        }
    }
    return false;
}

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