Question: I got parsed data object. The data is retuned by backend as JSON and has been parsed as data object in react-native client.

```
{
    "level1-key1": "value1",
    "level1-key2": "value2",
    "level1-key3": "value3",
    "level1-key4":{
        "level2-k1": "val1",
        "level2-k2": {
             "level3-k1": "v1",
             "level3-k2": "v2",
             "level3-k3": "v3"
        }
     }
}

```

I would like to get different level keys as an array of strings, i.e. I want to get level 2 keys, which are `["level2-k1", "level2-k2"]`.

I want to get level 3 keys, which are

```
["level3-k1", "level3-k2", "level3-k3"]

```

How achieve it?

Answer: 
The toast is outside the void, it should be:

```
public void Count_BMI() {
 Toast.makeText(getApplicationContext(),"This a toast message",Toast.LENGTH_LONG).show();
}

```
Need change:

```
public void Count_BMI() {
}
Toast.makeText(getApplicationContext(), "This a toast message", Toast.LENGTH_LONG) .show();

```

To:

```
public void Count_BMI() {
Toast.makeText(getApplicationContext(), "This a toast message", Toast.LENGTH_LONG) .show();
}

```

The problem is that you wrote the toast outside the brackets