如何在android中进行新活动？

Question

I've seen some solutions that people have posted, but I can't find the flaw in my code. It crashes on opening.

Here's my Main activity.

public class MainActivity extends Activity 
{
    Button guy, girl;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        guy = (Button) findViewById(R.id.bGuy);
        girl = (Button) findViewById(R.id.bGirl);

        guy.setOnClickListener(new View.OnClickListener() {
            public void onClick(View aView)
            {
                Intent toAnotherActivity = new Intent(aView.getContext(), ScreenGuy.class);
                startActivityForResult(toAnotherActivity, 0);
            }
        });
    }   
}   

And the .xml for it

<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/get_over"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dp"
    android:text="@string/get_over"
    android:textSize="20sp" />

<Button
    android:id="@+id/bGuy"
    android:layout_width="120dp"
    android:layout_height="40dp"
    android:layout_alignLeft="@+id/get_over"
    android:layout_below="@+id/get_over"
    android:layout_marginTop="66dp"
    android:text="@string/guy" 
    android:onClick="sendMessage"
     />

<Button
    android:id="@+id/bGirl"
    android:layout_width="120dp"
    android:layout_height="40dp"
    android:layout_alignBaseline="@+id/bGuy"
    android:layout_alignBottom="@+id/bGuy"
    android:layout_alignRight="@+id/get_over"
    android:text="@string/girl"
     />

I have another screen I want to move to on the button press of "Guy".

Answer 1

Intent intent = new Intent(MainActivity.this, ScreenGuy.class);
startActivity(intent);

EDIT: its like this because if you just say this, it refers to the context of the onclick listener class, not the activity

Answer 2

Use this:

Intent i = new Intent(FirstActivity.this, SecondActivity.class);
startActivity(i);

You do not pass the context of the clicked view, but the context of the application.

Answer 3

Change this:

Intent toAnotherActivity = new Intent(aView.getContext(), ScreenGuy.class);
startActivityForResult(toAnotherActivity, 0);

to this:

Intent toAnotherActivity = new Intent(MainActivity.this, ScreenGuy.class);
startActivity(toAnotherActivity);

For what you've said, you don't need to start the activity for result . Also, you were passing the Intent the wrong context: aView.getContext() . Pass it your class context.