集合转为字符串

public static String listToString(List<String> stringList) {
if (stringList == null) {
return null;
}
StringBuilder result = new StringBuilder();
boolean flag = false;
for (String string : stringList) {
if (flag) {
result.append(",");
} else {
flag = true;
}
result.append(string);
}
return result.toString();

}

//联网


public class NetWork {
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;
}


@SuppressWarnings("deprecation")
public static boolean isWifiConnected(Context context) {
if (context != null) {
ConnectivityManager mConnectivityManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mWiFiNetworkInfo = mConnectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (mWiFiNetworkInfo != null) {
return mWiFiNetworkInfo.isAvailable();
}
}
return false;
}


@SuppressWarnings("deprecation")
public static boolean isMobileConnected(Context context) {
if (context != null) {
ConnectivityManager mConnectivityManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mMobileNetworkInfo = mConnectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if (mMobileNetworkInfo != null) {
return mMobileNetworkInfo.isAvailable();
}
}
return false;
}


public static int getConnectedType(Context context) {
if (context != null) {
ConnectivityManager mConnectivityManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();
if (mNetworkInfo != null && mNetworkInfo.isAvailable()) {
return mNetworkInfo.getType();
}
}
return -1;
}
}

//打开本地文件


import java.io.File;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.net.Uri;


@SuppressLint("DefaultLocale")
public class GetUriMime {
/**
* 根据文件后缀名获得对应的MIME类型。
*/


public static String getMIMEType(File file) {
String type = "*/*";
String fName = file.getName();
// 获取后缀名前的分隔符"."在fName中的位置。
int dotIndex = fName.lastIndexOf(".");
if (dotIndex < 0) {
return type;
}
/* 获取文件的后缀名 */
String end = fName.substring(dotIndex, fName.length()).toLowerCase();
if ("".equals(end)) {
return type;
}
// 在MIME和文件类型的匹配表中找到对应的MIME类型。
for (int i = 0; i < MIME_MapTable.length; i++) {
if (end.equals(MIME_MapTable[i][0]))
type = MIME_MapTable[i][1];
}
return type;
}


/**
* 打开文件
* 
* @param file
*/
public static Intent openFile(File file) {
Intent intent = null;
try {
intent = new Intent("android.intent.action.VIEW");
intent.addCategory("android.intent.category.DEFAULT");
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
// 获取文件file的MIME类型
String type = getMIMEType(file);
// 设置intent的data和Type属性。
intent.setDataAndType(Uri.fromFile(file), type);
// 跳转
} catch (Exception e) {
e.printStackTrace();
}
return intent;


}


// 删除文件
public static void deleteFile(File file) {
if (file.exists()) { // 判断文件是否存在
if (file.isFile()) { // 判断是否是文件
file.delete(); // delete()方法 你应该知道 是删除的意思;
} else if (file.isDirectory()) { // 否则如果它是一个目录
File files[] = file.listFiles(); // 声明目录下所有的文件 files[];
for (int i = 0; i < files.length; i++) { // 遍历目录下所有的文件
deleteFile(files[i]); // 把每个文件 用这个方法进行迭代
}
}
file.delete();
}
}


// 建立一个MIME类型与文件后缀名的匹配表
public static String[][] MIME_MapTable = {
// {后缀名， MIME类型}
{ ".3gp", "video/3gpp" }, { ".apk", "application/vnd.android.package-archive" },
{ ".asf", "video/x-ms-asf" }, { ".avi", "video/x-msvideo" }, { ".bin", "application/octet-stream" },
{ ".bmp", "image/bmp" }, { ".c", "text/plain" }, { ".class", "application/octet-stream" },
{ ".conf", "text/plain" }, { ".cpp", "text/plain" }, { ".doc", "application/msword" },
{ ".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document" },
{ ".xls", "application/vnd.ms-excel" },
{ ".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" },
{ ".exe", "application/octet-stream" }, { ".gif", "image/gif" }, { ".gtar", "application/x-gtar" },
{ ".gz", "application/x-gzip" }, { ".h", "text/plain" }, { ".htm", "text/html" }, { ".html", "text/html" },
{ ".jar", "application/java-archive" }, { ".java", "text/plain" }, { ".jpeg", "image/jpeg" },
{ ".jpg", "image/jpeg" }, { ".js", "application/x-JavaScript" }, { ".log", "text/plain" },
{ ".m3u", "audio/x-mpegurl" }, { ".m4a", "audio/mp4a-latm" }, { ".m4b", "audio/mp4a-latm" },
{ ".m4p", "audio/mp4a-latm" }, { ".m4u", "video/vnd.mpegurl" }, { ".m4v", "video/x-m4v" },
{ ".mov", "video/quicktime" }, { ".mp2", "audio/x-mpeg" }, { ".mp3", "audio/x-mpeg" },
{ ".mp4", "video/mp4" }, { ".mpc", "application/vnd.mpohun.certificate" }, { ".mpe", "video/mpeg" },
{ ".mpeg", "video/mpeg" }, { ".mpg", "video/mpeg" }, { ".mpg4", "video/mp4" }, { ".mpga", "audio/mpeg" },
{ ".msg", "application/vnd.ms-outlook" }, { ".ogg", "audio/ogg" }, { ".pdf", "application/pdf" },
{ ".png", "image/png" }, { ".pps", "application/vnd.ms-powerpoint" },
{ ".ppt", "application/vnd.ms-powerpoint" },
{ ".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation" },
{ ".prop", "text/plain" }, { ".rc", "text/plain" }, { ".rmvb", "audio/x-pn-realaudio" },
{ ".rtf", "application/rtf" }, { ".sh", "text/plain" }, { ".tar", "application/x-tar" },
{ ".tgz", "application/x-compressed" }, { ".txt", "text/plain" }, { ".wav", "audio/x-wav" },
{ ".wma", "audio/x-ms-wma" }, { ".wmv", "audio/x-ms-wmv" }, { ".wps", "application/vnd.ms-works" },
{ ".xml", "text/plain" }, { ".z", "application/x-compress" }, { ".zip", "application/x-zip-compressed" },/*{".rar", "application/x-rar-compressed"},*/
{ "", "*/*" } };
}