材料设计和外部存储访问的最低/目标SDK版本应该是什么？

Question

I want to write a very simple app that only has 2 requirements. Support for material design and uses the phone internal storage.

So when I created the Android studio project my minSdkVersion was set to 21 and my targetSdkVersion was set to 26.

This gave me the following problem. When I wanted to get access to internal storage I couldn't because of the new runtime permission system. I figured I needed to write the code for requesting persmissions but then I run into the problem that the requestPermissions function requires a minSdkVersion of 23.

So, here is what I want. I want to make sure that my app works in any android version higher than 5. What is the right way to solve this permission issue and what should my minSdk and targetSdk be?

I want to set my minSdkVersion to 21 and be done with it, but I don't know what problems that might bring.

Answer 1

You should request the permissions using the Support Library. The official documentation explains pretty well the entire process: Requesting Permissions at Run Time . As this guide says:

using the support library is simpler, since your app doesn't need to check which version of Android it's running on before calling the methods

Answer 2

public boolean haveStoragePermission() {
        if (Build.VERSION.SDK_INT >= 23) {
            if (getApplicationContext().checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED &&
                    getApplicationContext().checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
                return true;
            } else {
                ActivityCompat.requestPermissions(AddPostActivity.this , new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
                return false;
            }
        }
        else {
            return true;
        }
    }

And add this method at the beginning of onCreate() method and don't forget to add those two permission into mainifest file.