Reputation: 175
I want to create something like theme changing day/night.
Here's the code:
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId()==R.id.menu_svijetlaTema){
/**Set background color*/
View view = this.getWindow().getDecorView();
view.setBackgroundColor(Color.parseColor("#ffffff"));
String[] values = getResources().getStringArray(R.array.pitanja);
final ArrayAdapter<CharSequence> adapter = new ArrayAdapter<CharSequence>(this, android.R.layout.simple_list_item_1, values){
@NonNull
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View a = super.getView(position, convertView, parent);
TextView boja = (TextView) a.findViewById(android.R.id.text1);
boja.setTextColor(Color.BLACK);
return a;
}
};
ListView listView = (ListView) findViewById(R.id.listView);
listView.setAdapter(adapter);
RelativeLayout layout = (RelativeLayout) findViewById(R.id.activity_second);
layout.setBackgroundColor(Color.WHITE);
} else if(item.getItemId()==R.id.menu_tamnaTema){
View view = this.getWindow().getDecorView();
view.setBackgroundColor(Color.parseColor("#4c635c"));
String[] values = getResources().getStringArray(R.array.pitanja);
final ArrayAdapter<CharSequence> adapter = new ArrayAdapter<CharSequence>(this, android.R.layout.simple_list_item_1, values){
@NonNull
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View a = super.getView(position, convertView, parent);
TextView boja = (TextView) a.findViewById(android.R.id.text1);
boja.setTextColor(Color.WHITE);
return a;
}
};
ListView listView = (ListView) findViewById(R.id.listView);
listView.setAdapter(adapter);
RelativeLayout layout = (RelativeLayout) findViewById(R.id.activity_second);
layout.setBackgroundColor(Color.BLACK);
}
return true;
}`
After this when I click item in menu app crashes, adapter is for changing ListView
, but RelativeLayout layout = (RelativeLayout) findViewById(R.id.activity_second);
layout.setBackgroundColor(Color.WHITE);
not working
I'm trying to change background color to MainActivity
and SecondActivity
from menu on MainActivity
.
Here's error :
--------- beginning of crash E/AndroidRuntime: FATAL EXCEPTION: main Process: hr.itot.vjezbaprvepomoci, PID: 2538 java.lang.NullPointerException: Attempt to invoke virtual method void
android.widget.RelativeLayout.setBackgroundColor(int)' on a null object reference at hr.itot.vjezbaprvepomoci.MainActivity.onOptionsItemSelected(MainActivity.java:605) at android.app.Activity.onMenuItemSelected(Activity.java:3204) at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:406) at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:195) at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:103) at android.support.v7.app.AppCompatDelegateImplV9.onMenuItemSelected(AppCompatDelegateImplV9.java:667) at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:810) at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:152) at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:957) at android.support.v7.view.menu.MenuPopup.onItemClick(MenuPopup.java:127) at android.widget.AdapterView.performItemClick(AdapterView.java:310) at android.widget.AbsListView.performItemClick(AbsListView.java:1155) at android.widget.AbsListView$PerformClick.run(AbsListView.java:3126) at android.widget.AbsListView$3.run(AbsListView.java:4041) at android.os.Handler.handleCallback(Handler.java:751) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6077) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) `
Upvotes: 0
Views: 692
Reputation: 1247
Add in manifest
<activity
android:name="com.alarm.main.MainActivity"
android:label="@string/app_name"
android:theme="@style/MyAppActionBarTheme" />
and create a themes.xml inside values folder and write down it
<resources>
<style name="MyAppActionBarTheme" parent="@android:style/Theme.Holo">
<item name="android:popupMenuStyle">@style/MyApp.PopupMenu</item>
<item name="android:itemTextAppearance">@style/TextAppearance</item>
</style>
<!-- The: background color for Action Bar overflow menu -->
<style name="MyApp.PopupMenu" parent="android:Widget.Holo.Light.ListPopupWindow">
<item name="android:popupBackground">#0b19ba</item>
</style>
<!-- Popup Menu Text Color styles -->
<style name="TextAppearance" parent="android:style/TextAppearance.Holo.Widget.ActionBar.Menu">
<item name="android:textColor">#ffffff</item>
</style>
Upvotes: 0
Reputation: 1891
To change overflow menu background add this to your Activity themes
<item name="android:itemBackground">@color/overflow_background</item>
Upvotes: 0