从类中解析JSON。 Android的

Question

There is a code with JSON. I am beginner and I do not understand this code.

Can anybody explain what I have?

And ways to make code as a working app.

public class G_JSON_Activity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_j__json_);

    final String json = "{  \n" +
            "\t\"id\": 9999,  \n" +
            "\t\"firstName\": \"Joe\",  \n" +
            "\t\"lastName\": \"Richard\"\n" +
            "}";
}

There are comments:

// (Button)bParse: parse 
// Set textview text from JSON: [firstname]+[ ]+[lastname]'s id is [id]

Answer 1

• You are subclassing actionbaractivity it gives actionbar functionality to the activity, some additional methods and properties that are not available to general activity.such as making tabs etc..

• super.onCreate(savedInstanceState); you tell the Dalvik VM to run your code in addition to the existing code in the onCreate() of the parent class.

• You are setting activity_j__json_ layout in contentview which means the xml ui will be shown in the actionbaraactivity

• then an constant string json variable is declared and assigned an json value.

You can still run the project if there is no compilation error in your project due to other project files such as activity_j__json_

-- Update:

I think you would have textview in the activity_j_json see if you have anything like this in it and not the id

 <TextView
    android:id="@+id/myTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:textSize="20sp" />

In the source code

    TextView mTextView = (TextView)findViewById(R.id.myTextView);

    mTextView.setText(json);