I am trying to show a pair of hidden buttons (using setVisibility(View.VISIBLE), within a RelativeLayout), but it doesn't always work. The button shows OK on a Galaxy Tab 10.1" but not in a smaller tablet (not sure which model), nor on an Android 4.0 emulator.
I randomly discovered that, for a certain TextView t, the following code causes the buttons to become visible:
t.setText(t.getText());
...
button.setVisibility(View.VISIBLE);
t is located in the same RelativeLayout but is not related to the buttons (their locations are independent and non-overlapping).
Edit: In case some Android dev wants to track this down...
I was able to reduce the code to the following layout that exhibits the problem on an Android 4.0.3 emulator but not a Galaxy Tab. I found that I need a SurfaceView or the problem does not occur (for example, change it to TextView and the problem disappears).
<?xml version="1.0" encoding="utf-8"?>
<!-- layout/test.xml -->
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/relativeLayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<SurfaceView
android:id="@+id/mapCtrl"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_above="@+id/bottomPanel"
android:text="Placeholder"
android:layout_marginTop="18dip" />
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:text="@string/map_mode_title" />
<!--=================================================-->
<!-- Bottom bar: current road name and current speed -->
<LinearLayout
android:id="@+id/bottomPanel"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="#f228"
android:orientation="horizontal"
android:textColor="#ffff" >
<Button
android:id="@+id/btnNavMode"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_marginRight="3dip"
android:textColor="#fff"
android:text="Switch to\nNav Mode" />
<RelativeLayout
android:id="@+id/currentStreetPanel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="onClick"
android:clickable="true"
android:orientation="vertical" >
<TextView
android:id="@+id/currentStreetHdg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Current street"
android:textColor="#fff"
android:textSize="10dip" />
<TextView
android:id="@+id/currentStreet"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/currentStreetHdg"
android:layout_marginTop="-8dip"
android:singleLine="true"
android:text="Current street"
android:textColor="#fff"
android:textSize="30dip" />
</RelativeLayout>
<RelativeLayout
android:id="@+id/RelativeLayout2"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:background="#ff606060"
android:orientation="vertical" >
<TextView
android:id="@+id/yourSpeedHdg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="3dip"
android:text="Your speed"
android:textColor="#fff"
android:textSize="10dip" />
<TextView
android:id="@+id/speed"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/yourSpeedHdg"
android:layout_marginLeft="3dip"
android:layout_marginTop="-8dip"
android:text="0"
android:textColor="#fff"
android:textSize="30dip" />
<TextView
android:id="@+id/speedUnit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/speed"
android:layout_marginLeft="5dip"
android:layout_toRightOf="@+id/speed"
android:text="kph"
android:textColor="#fff"
android:textSize="18dip" />
</RelativeLayout>
</LinearLayout>
<!--================-->
<!-- On-map buttons -->
<Button
android:id="@+id/btnClearRoute"
android:background="#F00"
android:textColor="#fff"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Clear\nroute"/>
<ZoomControls
android:id="@+id/zoomControls"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/mapCtrl"
android:layout_centerHorizontal="true"
android:layout_marginBottom="-25dip"
android:orientation="horizontal" />
<Button
android:id="@+id/btnFindRoute"
android:layout_width="100dip"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/mapCtrl"
android:layout_alignParentRight="true"
android:layout_marginRight="2dip"
android:layout_marginBottom="65dip"
android:text="Route to selected location"
android:textSize="17dip"/>
<Button
android:id="@+id/btnUnselect"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/btnFindRoute"
android:layout_alignTop="@+id/btnFindRoute"
android:layout_alignParentLeft="true"
android:layout_marginLeft="2dip"
android:text="Unselect" />
<LinearLayout
android:id="@+id/showMePanel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/btnFindRoute"
android:layout_alignRight="@+id/btnFindRoute"
android:layout_alignLeft="@+id/btnFindRoute"
android:padding="4dip"
android:background="#bbbb"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Show me..."
android:textColor="#fff"/>
<Button
android:id="@+id/btnShowVehicle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="My car"/>
<Button
android:id="@+id/btnShowRoute"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="The route"/>
<Button
android:id="@+id/btnShowDestination"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Destination"/>
<Button
android:id="@+id/btnShowMap"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="The map"/>
</LinearLayout>
</RelativeLayout>
The Activity class simply toggles the visibility of the two buttons when any of the buttons are clicked. Again, on some devices it works, on others it does not.
package mentor.simplegps;
import android.app.*;
import android.os.Bundle;
import android.view.*;
import android.widget.*;
public class TestActivity extends Activity implements View.OnClickListener
{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.test);
boilerplate();
setVisibilities();
}
Button _btnShowMap, _btnShowVehicle, _btnShowRoute, _btnShowDestination;
Button _btnUnselect, _btnFindRoute, _btnNavMode;
TextView _title;
void boilerplate()
{
_btnUnselect = attachBtn(R.id.btnUnselect);
_btnShowMap = attachBtn(R.id.btnShowMap);
_btnShowVehicle = attachBtn(R.id.btnShowVehicle);
_btnShowRoute = attachBtn(R.id.btnShowRoute);
_btnShowDestination = attachBtn(R.id.btnShowDestination);
_btnFindRoute = attachBtn(R.id.btnFindRoute);
_btnNavMode = attachBtn(R.id.btnNavMode);
_title = (TextView)findViewById(R.id.title);
}
private Button attachBtn(int btnId) {
Button b = (Button)findViewById(btnId);
b.setOnClickListener(this);
return b;
}
boolean haveSel;
public void onClick(View v)
{
haveSel = !haveSel;
setVisibilities();
}
void setVisibilities()
{
_btnFindRoute.setVisibility(haveSel ? View.VISIBLE : View.INVISIBLE);
_btnUnselect.setVisibility (haveSel ? View.VISIBLE : View.INVISIBLE);
// Fixes the problem
//_title.setText(_title.getText());
}
}