Question

我在imgFile.exist()上的if条件是假的，但是当Log.d打印出结果时，我可以看到该文件存在于路径中。

我只是尝试从路径加载图像，将其作为活动微缩图像的背景

我的清单android.permission.WRITE_EXTERNAL_STORAGE

中也有读/写权限

加载图片：

File imgFile = new  File(getRowItem.getImgURI().trim());
Log.d("TAGG", "FILE PATH: " + imgFile.getPath());
// imgFile's path: /storage/emulated/0/TravelDiary/img_1461684314337.jpg


if(imgFile.exists()){

    //it never reach inside here

    Log.d("TAGG", "FILE ABSOLUTE PATH: " + imgFile.getAbsolutePath());
    Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
    Drawable drawable = new BitmapDrawable(getResources(), myBitmap);
    imageView.setBackground(drawable);
}

保存图片：

当来自intentChooser的用户选择从相机捕捉图像或从gallary中选择图像时，会保存图像

 public void ImagePicker(View v){

if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
        if (PackageManager.PERMISSION_GRANTED == ActivityCompat.checkSelfPermission(this,  Manifest.permission.WRITE_EXTERNAL_STORAGE) && PackageManager.PERMISSION_GRANTED  == ActivityCompat.checkSelfPermission(this,  Manifest.permission.READ_EXTERNAL_STORAGE)) {

            final File rootdir = new File(Environment.getExternalStorageDirectory() + File.separator + "TravelDiary");
            rootdir.mkdirs();
            final String filename = "img_" + System.currentTimeMillis() + ".jpg";
            final File sdImageMainDirecotry = new File(rootdir, filename);
            outputFileUri = Uri.fromFile(sdImageMainDirecotry);
            ...
            ...


     } else {
            //if permission is not granted, then we ask for it
            ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE,  Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
       }else{
        Toast.makeText(this, "External storage not available", Toast.LENGTH_SHORT).show();
    }
}

我的清单中的权限：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.muddii.traveldiary">

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

 ...
 ...
 ...

</manifest>

Answer 1

在清单中添加此内容。

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

Answer 2

gradle中的SDK值是多少？如果是23，那么你需要在运行时请求许可。

http://developer.android.com/training/permissions/requesting.html

Answer 3

试试这个而不是imgFile.exists（）

File file = new File(path);
if (!file.isFile()) {
    //your code
}else{
//your code
}

为什么我的文件不存在，即使我给它一条存在的路径？

3 个答案: