Android 启动 Activity 2 但 rest 在 MainActivity

Question

I have MainActivity which has got a button that opens Activity 2. Everything from Activity 2 should be calculated and be run but the user should rest at MainActivity? How do I do this?

I found a solution where I dont run the "setContentView()" but then my app crashes.

Answer 1

You want to change the view of application but does not want the user to change activity.

Use two different layout in xml file with id:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent">
   <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:id="@+id/first_view">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Button1"
            android:id="@+id/button"
            android:background="#358a32" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:id="@+id/second_view"
        android:visibility="gone">
    </LinearLayout>
<LinearLayout>

Then onclick of button:

public class MainActivity extends Activity {
    boolean firstViewOff = false;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);      
        Button button = (Button) findViewById(R.id.button1);
        LinearLayout first_view = (LinearLayout) findViewById(R.id.first_view);
        LinearLayout second_view = (LinearLayout) findViewById(R.id.second_view);
        button.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                firstViewOff = true;
                first_view.setVisibility(View.GONE);
                second_view.setVisibility(View.VISIBLE);
            }
        });
    }
    @override
    public void onBackPressed(){
      super.onBackPressed();
      if(firstViewOff){
        second_view.setVisibility(View.GONE);
        first_view.setVisibility(View.VISIBLE);
        firstViewOff = false;
      }
    }

}

Why i attached backpressed:

Because when user backpress then it will just directly show firstview without closing,