java每当我第一次启动应用程序时，应用程序崩溃，然后它向我请求用户权限

Question

我的Android应用程序在第一次启动时崩溃，它询问我有关用户呼叫权限的问题。当我再次启动我的应用程序时，它会正常工作。我尝试了以下代码

public void loadContactList() {

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && checkSelfPermission(Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
        requestPermissions(new String[]{Manifest.permission.READ_CONTACTS}, PERMISSIONS_REQUEST_READ_CONTACTS);
    } else {.....}
}

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions,int[] grantResults) {
    if (requestCode == PERMISSIONS_REQUEST_READ_CONTACTS) {
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            loadContactList();
        } else {
            Toast.makeText(this, "Until you grant the permission, we canot display the list", Toast.LENGTH_SHORT).show();
        }
    }
}

Answer 1

添加以下代码

String[] appPermissions =
            {Manifest.permission.READ_CONTACTS,
                    Manifest.permission.WRITE_CONTACTS};
    int PERMISSIONS_REQUEST_CODE = 234;

在创建时从您的应用程序调用此方法

checkAndRequestPermissions();

将以下方法添加到主要活动中

public boolean checkAndRequestPermissions() {
        List<String> listPermissionsNeeded = new ArrayList<>();
        for (String perm : appPermissions) {
            if (ContextCompat.checkSelfPermission(this, perm) != PackageManager.PERMISSION_GRANTED) {
                listPermissionsNeeded.add(perm);
            }
        }
        if (!listPermissionsNeeded.isEmpty()) {
            ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]), PERMISSIONS_REQUEST_CODE);
            return false;
        }
        return true;
    }

Answer 2

我刚刚解决了一个例外。我做了两件事。首先，我通过
删除了联系人的初始化 ^从loadContactList()中{}并将其添加到onCreate()中，然后我刚刚将loadContactList()的返回数据类型从void更改为list。然后我在loadContacts（）中返回了联系人，以便loadListView()可以获取此列表并将其显示在列表视图中

Answer 3

你的代码是对的，但是你把代码设置在了错误的地方，让我们试试这个，它肯定会帮你

In Your Main Activity...

private int STORAGE_PERMISSION_CODE = 1;

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

    if (ContextCompat.checkSelfPermission(MainActivity.this,
            Manifest.permission.WRITE_EXTERNAL_STORAGE) == 
  PackageManager.PERMISSION_GRANTED) {
        filter();
        Toast.makeText(this, ""+arrayList, Toast.LENGTH_SHORT).show();
    } else {
        Permission.requestStoragePermission(MainActivity.this,
                  STORAGE_PERMISSION_CODE);
    }

}//on create closed

权限方法

//                -RuntimePermission              -//
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] 
    permissions, @NonNull int[] grantResults) {
    if (requestCode == STORAGE_PERMISSION_CODE)  {
        if (grantResults.length > 0 && grantResults[0] == 
     PackageManager.PERMISSION_GRANTED) {
            filter();
        } else {
            Toast.makeText(this, "Permission DENIED", Toast.LENGTH_SHORT).show();

Permission.requestStoragePermission(MainActivity.this,STORAGE_PERMISSION_CODE);
        }
    }
}

之后，让java类获得权限

public class Permission {
public static void requestStoragePermission(final Activity activity, final int 
       STORAGE_PERMISSION_CODE) {
    if (ActivityCompat.shouldShowRequestPermissionRationale(activity,
            Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
        new AlertDialog.Builder(activity)
                .setTitle("Permission needed")
                .setMessage("This permission is needed because of this and that")
                .setPositiveButton("ok", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        ActivityCompat.requestPermissions(activity,
                                new String[] 
        {Manifest.permission.WRITE_EXTERNAL_STORAGE}, STORAGE_PERMISSION_CODE);
                    }
                })
                .setNegativeButton("cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                })
                .create().show();
    } else {
        ActivityCompat.requestPermissions(activity,
                new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 
   STORAGE_PERMISSION_CODE);
    }
}

}

你要记住的主要事情是把你的工作方法放在正确的地方，比如我的is filter（）

它对你有用，因为当我陷入同样的处境时，它对我有用