Android Tips

Toast in fragment

When we want to make toast in fragments, we should use

getActivity() to get application context.

Toast.makeText(getActivity(), "Here is a toast", Toast.LENGTH_LONG).show();

findViewById in fragment

When we want to find view in onCreateView() in a fragment, we should first inflate the layout,

View view = inflater.inflate(R.layout.fragment_2, parent, false);
//This view should be returned at the end

then use view to find the view that we want.

(Button) view.findViewById(R.layout.btn);

Navigation drawer 1

While using navigation drawer, we can implements actions in selectItem(int position). There is no need to delete the preset code (which is indicated below). These codes are used for close drawer, etc. Unless you want to do something else.

private void selectItem(int position) {
mCurrentSelectedPosition = position;
if (mDrawerListView != null) {
mDrawerListView.setItemChecked(position, true);
}
if (mDrawerLayout != null) {
mDrawerLayout.closeDrawer(mFragmentContainerView);
}
if (mCallbacks != null) {
mCallbacks.onNavigationDrawerItemSelected(position);
}

Just simply use a switch to get the position that user selected.

private void selectItem(int position) {
//Preset codes
switch (position) {
case 0:
//Things to do.
break;
case 1:
//Things to do.
break;
default:
break;
}

ScrollView fill page

Just simply use the XML code follow

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fillViewport="true"
android:fadeScrollbars="false"
android:scrollbars="vertical" >

Create Activity

In function onCreate of an Activity, we should

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.nameOfLayout);
setTitle(R.string.nameOfLayout);
}

And,

PersistableBundle persistentState

shall not be one of the argument of function onCreate.

Moreover,

super.onCreate(savedInstanceState);

shall be written before setContentView, otherwise, the layout may not be load into the Activity.