Question

i’m still porting a J2ME app to Android and now my problem is with the GUI.
For what i’ve seen, Android’s Activities are great, but my J2ME is filled with the classic:

public void switchDisplayable(Alert alert, Displayable nextDisplayable) {
        Display display = getDisplay();
        if (alert == null)
            display.setCurrent(nextDisplayable);
        else 
            display.setCurrent(alert, nextDisplayable);
}

I just can’t make every Displayable to an Activity, so i thought about replacing them with View. I tried that but it just doesn’t works, the app doesn’t changes the screen.

Update:

Thanks for answering, but placed al vews inside FrameLayout and still nothing. This is the core of my test code, so you can check it out:

public class TestActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);        
        setContentView(R.layout.main);
        TextView t = (TextView)findViewById(R.id.text); // Shows "Hi"
        showDialog(); // it just shows a dialog asking if the user wants to change screen

    }
    showDialog() {
        // in OnClick()... i do the following, and here is where it fails, i tried so far:        
        TestView testv= new MarcoLoco(MFActivity.this);
    setContentView(testv);
        testv.invalidate();
    testv.requestFocus();
    testv.showMeSomething();
    }


public class TestView extends View{
    private Context context;
    TextView tv;    
    public TestView(Context context) {
        super(context);
        this.context=context;
    }   
    public void showMeSomething() {
        tv = (TextView)findViewById(R.id.tessto); // it should show "Bye"
    }
}

After the OnClick the “Hi” dissapears from the screen but nothing appears, no “Bye”.

Why, oh, why!?

Answer 1

I don’t have any expirience with Java ME, but this might help you

Put your Views inside a FrameLayout, then you can use

mViewA.setVisibility(View.VISIBLE);
mViewB.setVisibility(View.GONE);
mViewA.requestFocus();

to switch between diffrent views

EDIT:

Here is a short example program that toggles between 2 textviews:

public class test extends Activity {
    boolean showTV1 = true;

    OnClickListener ocl = new OnClickListener() {
        @Override
        public void onClick(View v) {
            showTV1= !showTV1;
            if (showTV1){
                tv1.setVisibility(View.VISIBLE);
                tv2.setVisibility(View.GONE);
                tv1.requestFocus();
            } else {
                tv2.setVisibility(View.VISIBLE);
                tv1.setVisibility(View.GONE);
                tv2.requestFocus();
            }
        }
    };

    private TextView tv1, tv2;  

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv1 = (TextView) findViewById(R.id.TextView01); 
        tv2 = (TextView) findViewById(R.id.TextView02);

        tv1.setOnClickListener(ocl);
        tv2.setOnClickListener(ocl);
    }
}

and main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/frameLayout01" android:layout_width="fill_parent"
    android:layout_height="fill_parent"  >
    <TextView android:id="@+id/TextView01" android:layout_width="fill_parent"
        android:layout_height="fill_parent" android:background="#0f0"
        android:text="Hi" />
    <TextView android:id="@+id/TextView02" android:layout_width="fill_parent"
        android:layout_height="fill_parent" android:background="#f00"
        android:text="Bye" android:visibility="gone"/>
</FrameLayout>