Question

我正在尝试将存储在“图片”目录中的图像显示为listView。在MainActivity中，我创建了如下变量：

  //declare variables required for ListView
   private String[] FilePathStrings; //holds file path of the images captured.
   private String[] FileNameStrings;  //holds name of the images captured.
   private File[] listImage;    //holds the images.
   ListView list;
   ListViewAdapter adapter;
   File file;

然后在onCreate方法中，我调用populateListArray（）来填充String和File数组。

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //Populate the list array with image and file name
    populateListArray();

    //create ListAdapter and bind it to ListView
    createListAdapter();

}

和PopulateListArray（）如下：

   void populateListArray(){

    // Check whether SD Card exists
    if (!Environment.getExternalStorageState().equals(
            Environment.MEDIA_MOUNTED)) {
        Toast.makeText(this, "Error! No SDCARD Found!", Toast.LENGTH_LONG)
                .show();
    } else {
        // Locate the image folder in your SD Card
        file = new File(Environment.getExternalStorageDirectory()
                + File.separator + "Pictures");  //'Pictures' is the folder where google cam
                                                  // stores pictures.
        Log.i(MYTAG, "file = " +file); // file = /storage/sdcard0/Pictures
        Log.i(MYTAG, "file.isDirectory = " +file.isDirectory()); // file.isDirectory() is always returning false
    }


    //If 'Pictures' directory exists then populate the corresponding arrays

    if (file.isDirectory())   // following code is never executed as file.isDirectory() is always false.
    {
        listImage = file.listFiles();
        Log.i(MYTAG, "listImage = " +listImage);
        // Create a String array for FilePathStrings
        FilePathStrings = new String[listImage.length];

        Log.i(MYTAG, "FilePathStrings = " +listImage.length);
        // Create a String array for FileNameStrings
        FileNameStrings = new String[listImage.length];

        for (int i = 0; i < listImage.length; i++) {
            // Get the path of the image file
            FilePathStrings[i] = listImage[i].getAbsolutePath();
            // Get the name image file
            FileNameStrings[i] = listImage[i].getName();
        }
    } //endif

}

以下是生成的调试代码：

07-24 23:07:30.417  26364-26364/com.example.lib.dailyselfie I/Lab-Selfie﹕ file = /storage/sdcard0/Pictures
07-24 23:07:30.417  26364-26364/com.example.lib.dailyselfie I/Lab-Selfie﹕ file.isDirectory = false
07-24 23:07:30.587  26364-26364/com.example.lib.dailyselfie D/libEGL﹕ loaded /system/lib/egl/libEGL_adreno200.so
07-24 23:07:30.647  26364-26364/com.example.lib.dailyselfie D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_adreno200.so
07-24 23:07:30.657  26364-26364/com.example.lib.dailyselfie D/libEGL﹕ loaded /system/lib/egl/libGLESv2_adreno200.so

我不明白为什么尽管'Pictures'是一个目录，file.isDirectory（）仍然返回'false'？请帮忙。

Answer 1

确保您拥有访问＆＃39;图片＆＃39;所需的权限。目录。将以下内容添加到AndroidManifest.xml：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

file.isDirectory（）为目录

1 个答案: