解决安卓7.0系统写入SD卡权限失败问题
余温
2018年05月09日 18时07分
android
如图所示,在mainfest文件中声明了SD卡的读和写权限,仍旧报错:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission>
安卓23.0版本以上,不仅仅要设置上面的权限,还要在对SD卡有读写操作的地方授权,下面是公共类:
import android.Manifest;import android.app.Activity;import android.content.pm.PackageManager;import android.support.v4.app.ActivityCompat;public class PermisionUtils { // Storage Permissions private static final int REQUEST_EXTERNAL_STORAGE = 1; private static String[] PERMISSIONS_STORAGE = { Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}; /** * Checks if the app has permission to write to device storage * If the app does not has permission then the user will be prompted to * grant permissions * * @param activity */ public static void verifyStoragePermissions(Activity activity) { // Check if we have write permission int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) { // We don't have permission so prompt the user ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE); } } }
然后直接在需要授权的地方调用:
verifyStoragePermissions(this);
在SD卡写入xml文件
//生成XML文件 public void click(View v) throws IOException { //获取实例 try { verifyStoragePermissions(this);//请求写入权限 XmlSerializer serializer = Xml.newSerializer(); //设置序列化 File file = new File(Environment.getExternalStorageDirectory().getPath(), "texe.xml"); FileOutputStream fos = new FileOutputStream(file); serializer.setOutput(fos, "utf-8"); //写文件头 serializer.startDocument("utf-8", true); //写根节点 serializer.startTag(null, "smss"); serializer.startTag(null, "sms"); serializer.text("知乎"); serializer.endTag(null, "sms"); serializer.endTag(null, "smss"); fos.close(); System.out.println("保存成功"); } catch (Exception e) { System.out.println("保存失败"); System.out.println("--------------------------------------------"); e.printStackTrace(); System.out.println("-----------------------------------"); } }
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