Question

我对android缓存有些困惑，在运行时android app cache需要外部存储读写权限。任何人都可以帮助我解决这个困惑。例如，

File tempFile = File.createTempFile("img", ".png", getExternalCacheDir());
String imgPath = tempFile.getAbsolutePath();

Answer 1

您必须在运行时https://developer.android.com/training/permissions/requesting.html，示例，

询问权限

public void requestPermissionForExternalStorage() {
        if (ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
            Toast.makeText(activity, "External Storage permission needed. Please allow in App Settings for additional functionality.", Toast.LENGTH_LONG).show();
        } else {
            ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, EXTERNAL_STORAGE_PERMISSION_REQUEST_CODE);
        }
}

Answer 2

试试这个，

存储权限

    private static final int REQUEST_STORAGE = 112;



  if (Build.VERSION.SDK_INT >= 23) {
        String[] PERMISSIONS = {android.Manifest.permission.WRITE_EXTERNAL_STORAGE,android.Manifest.permission.READ_EXTERNAL_STORAGE};
        if (!hasPermissions(mContext, PERMISSIONS)) {
            ActivityCompat.requestPermissions((Activity) mContext, PERMISSIONS, REQUEST_STORAGE );
        } else {

            File tempFile = File.createTempFile("img", ".png", getExternalCacheDir());
            imgPath = tempFile.getAbsolutePath();
        }
    } else {

        File tempFile = File.createTempFile("img", ".png", getExternalCacheDir());
         imgPath = tempFile.getAbsolutePath();
    }

获取权限结果

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case REQUEST_STORAGE: {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                   File tempFile = File.createTempFile("img", ".png", getExternalCacheDir());
                   imgPath = tempFile.getAbsolutePath();
                } 
            }
        }
    }

检查marshmallow的权限

    private static boolean hasPermissions(Context context, String... permissions) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && context != null && permissions != null) {
            for (String permission : permissions) {
                if (ActivityCompat.checkSelfPermission(context, permission) != PackageManager.PERMISSION_GRANTED) {
                    return false;
                }

            }
        }
        return true;
    }

Android应用缓存需要存储权限

2 个答案: