获取App信息

获取VersionCode：

  /**
     * 得到VersionCode
     * @return
     */
    public int getVersionCode(){
        String packageName =  getApplicationContext().getPackageName();
        try {
            PackageInfo packageInfo  = getApplicationContext().getPackageManager().getPackageInfo(packageName,0);
            return packageInfo.versionCode;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return -1;
    }

获取VersionName：

    /**
     * 得到VersionName
     * @return
     */
    public String getVersionName(){
        String packageName = getApplicationContext().getPackageName();
        try {
            PackageInfo packageInfo = getApplicationContext().getPackageManager().getPackageInfo(packageName,0);
            return packageInfo.versionName;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }

获取Application名称：

    /**
     * 得到Application的名称
     * @return
     */
    public String getApplicationName(){
        String packageName = getApplicationContext().getPackageName();
        try {
            ApplicationInfo applicationInfo = getApplicationContext().getPackageManager().getApplicationInfo(packageName,0);
            String applicaiontName = (String) getApplicationContext().getPackageManager().getApplicationLabel(applicationInfo);
            return applicaiontName;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }

判断一个App是否正在运行：

    /**
     * 判断一个App是否运行   不需要任何权限
     * @return
     */
    public boolean isRunning(){
        String packageName = getApplicationContext().getPackageName();
        ActivityManager am = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.RunningAppProcessInfo> infos = am.getRunningAppProcesses();
        for(ActivityManager.RunningAppProcessInfo rapi : infos){
            if(rapi.processName.equals(packageName)){
                return true;
            }
        }
        return false;
    }

判断一个Activity是否在前台：需要权限： android.permission.REAL_GET_TASKS （使用于 L以下，对于L以上则使用am.getRunningAppProcesses()方法）

    /**
     * 判断一个Activity是否在前台运行
     * @param activityName
     * @return
     */
    public boolean isTopActivity(String activityName){
        ActivityManager manager = (ActivityManager) getApplicationContext().getSystemService(getApplicationContext().ACTIVITY_SERVICE);
        List<ActivityManager.RunningTaskInfo> runningTaskInfos = manager.getRunningTasks(1);//maxNum限制要获取的数量
        String cmpNameTemp = null;
        if(runningTaskInfos != null){
            cmpNameTemp = runningTaskInfos.get(0).topActivity.getShortClassName();//info.topActivity.getPackageName()得到包的名字
        }

        if(cmpNameTemp == null){
            return false;
        }
        return cmpNameTemp.endsWith(activityName);

    }

获取应用的公钥签名：

    /**
     * 获取应用公钥签名
     * @return
     */
    public Signature getSign(){
        PackageInfo pi;
        Signature sign = null;
        try {
            pi = getApplicationContext().getPackageManager().getPackageInfo(getApplicationContext().getPackageName(),PackageManager.GET_SIGNATURES);
            sign = pi.signatures[0];
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return sign;
    }

比较当前签名HashCode和预设的HashCode：

    /**
     * 比较当前签名HashCode和预设的HashCode
     * @param presetHashCode
     * @return
     */
    public boolean signCheckWithHashCode(int presetHashCode){
        Signature signature = getSign();
        return signature.hashCode() == presetHashCode;
    }

数据操作：

   /**
     * 删除数据：cache,file,share prefs,databases
     */
    public void clear(){
        clearCache(getApplicationContext());
        clearFiles(getApplicationContext());
        clearSharedPreference(getApplicationContext());
        clearDataBase(getApplicationContext());
    }

    /**
     * 删除应用数据库目录
     * @param context
     */
    public void clearDataBase(Context context){
        delete(new File("/data/data/" + context.getPackageName() + "/databases"),true);
    }

    /**
     * 删除应用SharedPrefrence目录
     * @param context
     */
    public void clearSharedPreference(Context context){
        delete(new File("/data/data/" + context.getPackageName() + "/shared_prefs"), true);
    }

    /**
     * 删除应用文件目录
     * @param applicationContext
     */
    private void clearFiles(Context applicationContext) {
        delete(getApplicationContext().getFilesDir(),true);
    }

    /**
     * 删除应用缓存目录
     * @param directory
     * @param b
     */
    private void clearCache(Context applicationContext) {
        delete(getApplicationContext().getCacheDir(), true);
        delete(getApplicationContext().getExternalCacheDir(), true);
    }



    private void delete(File directory, boolean b) {
        if(directory != null && directory.exists()){
            if(directory.isDirectory()){
                for(File subDirectory : directory.listFiles()){
                    delete(subDirectory,false);
                }
            }
            if(!b){
                directory.delete();
            }
        }
    }