Question

public void GetFiles(String Path, String Extension, boolean IsIterative) 
    {
        File[] files = new File(Path).listFiles();
        Map<String , String> map ;
        for (int i = 0; i < files.length; i++)
        {
            File f = files[i];
            if (f.isFile())
            {
                if (f.getPath().substring(f.getPath().length() - Extension.length()).equals(Extension)) 
                {
                    map = new HashMap<String, String>();
                    map.put("img", f.getPath());
                    map.put("name", f.getName());
                    lstPics.add(map);
                }
                if (!IsIterative)
                    break;
            }
            else if (f.isDirectory() && f.getPath().indexOf("/.") == -1) 
                GetFiles(f.getPath(), Extension, IsIterative);
        }
    }

为什么它在android 4.4中工作正常，并且在android 6.0中发生了错误？ java.lang.NullPointerException：尝试获取null数组的长度 我使用三星note 4运行android 4.4.4 我使用nexus 5运行andoroid 6.0。

10-21 11:55:03.891 23515 23515 E AndroidRuntime: java.lang.NullPointerException: Attempt to get length of null array
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at qjizho.vrlauncher.Launcher.GetFiles(Launcher.java:137)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at qjizho.vrlauncher.Launcher$1.onItemClick(Launcher.java:58)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.widget.AdapterView.performItemClick(AdapterView.java:310)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.widget.AbsListView.performItemClick(AbsListView.java:1145)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.widget.AbsListView$PerformClick.run(AbsListView.java:3042)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.widget.AbsListView$3.run(AbsListView.java:3879)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.os.Handler.handleCallback(Handler.java:739)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.os.Handler.dispatchMessage(Handler.java:95)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.os.Looper.loop(Looper.java:148)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at android.app.ActivityThread.main(ActivityThread.java:5417)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at java.lang.reflect.Method.invoke(Native Method)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
10-21 11:55:03.891 23515 23515 E AndroidRuntime:    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Answer 1

这是因为您没有存储权限，默认情况下不会授予Android M存储空间。

请发布您的目标SDK是什么？你也在AndroidManifest.xml中要求存储权限吗？

 public void GetFiles(String Path, String Extension, boolean IsIterative) 
        {
            File[] files = new File(Path).listFiles(); <== This particular line is working fine no issue
            Map<String , String> map ;
            for (int i = 0; i < files.length; i++) <== this line is giving the Null Pointer Exception because since you don't have storage permission, so files are coming null.
            {
                File f = files[i];
                if (f.isFile())
                {
                    if (f.getPath().substring(f.getPath().length() - Extension.length()).equals(Extension)) 
                    {
                        map = new HashMap<String, String>();
                        map.put("img", f.getPath());
                        map.put("name", f.getName());
                        lstPics.add(map);
                    }
                    if (!IsIterative)
                        break;
                }
                else if (f.isDirectory() && f.getPath().indexOf("/.") == -1) 
                    GetFiles(f.getPath(), Extension, IsIterative);
            }
        }

为什么＆＃34;新文件（路径）＆＃34;无法在Android 6.0中运行

1 个答案: