Develop Reference

Android Studio error after splash

I have followed and tutorial for 4 times to make a splash screen but after the splash screen the app gives an error and closes. The splash screen has an image which stays for 4 second and the next screen has an webviewer, above the viewer the title bar needs to be there .Any idea?
Android Honey Comb 3.0 is set as default
The Splash.java :
package nl.broodje.app.broodje;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
/**
* Created by Christiaan on 14-11-2015.
*/
public class Splash extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.splash_screen);
Thread myThread = new Thread(){
#Override
public void run() {
try {
sleep(3000);
Intent startMainScreen = new Intent(getApplicationContext(), MainActivity.class);
startActivity(startMainScreen);
finish();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
myThread.start();
}
}
The splash_screen.xml :
<?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">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="#drawable/logo"
android:id="#+id/imageView"
android:layout_gravity="center_vertical" />
</LinearLayout>
The content_main.xml :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".MainActivity"
tools:showIn="#layout/activity_main">
<WebView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/webView"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
</RelativeLayout>
The activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:fitsSystemWindows="true"
tools:context=".MainActivity">
<android.support.design.widget.AppBarLayout android:layout_height="wrap_content"
android:layout_width="match_parent" android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar android:id="#+id/toolbar"
android:layout_width="match_parent" android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary" app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="#layout/content_main" />
<android.support.design.widget.FloatingActionButton android:id="#+id/fab"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="bottom|end" android:layout_margin="#dimen/fab_margin"
android:src="#android:drawable/ic_dialog_email" />
</android.support.design.widget.CoordinatorLayout>
The MainActivity.java :
package nl.broodjep.app.broodje;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.WebView;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String url = "http://broodje.nl/";
WebView view=(WebView) this.findViewById(R.id.webView);
view.getSettings() .setJavaScriptEnabled(true);
view.loadUrl(url);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
The AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="nl.broodje.app.broodje" >
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="#drawable/icoon"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<activity
android:name=".Splash"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity"/>
</application>
</manifest>

Since MainActivity extends AppCompatActivity, and you're setting your own ActionBar, MainActivity needs to have a NoActionBar theme, like the splash screen.
<activity android:name=".MainActivity"
android:theme="#style/AppTheme.NoActionBar" />

Android app icon doesn't show on actionbar

I am creating an android app using eclipse and I have a problem. the app icon doesn't show on actionbar. can anybody tell me what's wrong? here is the manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.gowemto.gnoulashe"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="16"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/Theme.AppCompat.Light" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".CalcResultActivity"
android:label="#string/title_activity_calc_result"
android:parentActivityName=".MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.gowemto.gnoulashe.MainActivity" />
</activity>
</application>
</manifest>
and here's the main activity code:
package com.gowemto.gnoulashe;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
public class MainActivity extends ActionBarActivity {
String result;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void intent1(View view) {
Intent intent = new Intent(this, CalcResultActivity.class);
startActivity(intent);
}
}
and here's the xml file of main activity:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="16sp"
android:text="#string/welcome_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/add_the_dates"
android:onClick="intent1" />
</LinearLayout>
and this is what the actionbar look like when I run the app: http://i.imgur.com/jADDz7b.png
The app doesn't show any errors, and the icon is put in the right way in the directories. so can anyone tell me what's the problem and how can I fix it?

The problem with #ZsoltBoldizsár's answer is that you are using ActionBarActivity. Change getActionBar() to getSupportActionBar()
Add the following code in onCreate(Bundle) after you call super.onCreate(Bundle):
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setIcon(R.drawable.ic_launcher);
Appcompat-v7 automatically disables setDisplayShowHomeEnabled so you must set it to true to show an icon.

You need to configure the actionbar. Read the documentation, but the line below might help you.
getActionBar().setHomeButtonEnabled(true);
getActionBar().setIcon(here comes your drawable id) (eg. R.drawable.ic_launcher)

Try with this:
ActionBar ab = getActionBar();
ab.setHomeButtonEnabled(true);
ab.setDisplayHomeAsUpEnabled(true);
ab.setDisplayShowTitleEnabled(false);
ab.setDisplayShowCustomEnabled(true);
ab.setTitle(Html.fromHtml("your text"));
ColorDrawable colorDrawable = new ColorDrawable(Color.parseColor(your_colorCode));
ab.show();

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.myfirstapp/com.example.myfirstapp.DisplayMessageActivity}

I’m following the android tutorial First App in the link below:
https://developer.android.com/training/basics/firstapp/starting-activity.html
The app can be launched in the emulator but the problem is when I click on the button “send, the application crashed with the message “unfortunately, my fist app has stopped”.
I think I did follow the instructions in the tutorial and can’t figure out where is the problem from.
Logcat send this message:
02-12 16:19:36.031: E/AndroidRuntime(786): java.lang.RuntimeException:
Unable to instantiate activity
ComponentInfo{com.example.myfirstapp/com.example.myfirstapp.DisplayMessageActivity}:
java.lang.NullPointerException
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<EditText android:id="#+id/edit_message"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="#string/edit_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_send"
android:onClick="sendMessage" />
</LinearLayout>
MAinActivity.java
package com.example.myfirstapp;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
/** Called when the user clicks the Send button */
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
// Do something in response to button
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
activity_display_message.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".DisplayMessageActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
</RelativeLayout>
DisplayMessageActivity.java
package com.example.myfirstapp;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.NavUtils;
import android.view.MenuItem;
import android.widget.TextView;
public class DisplayMessageActivity extends Activity {
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
#SuppressLint("NewApi")
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the message from the intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);
// Make sure we're running on Honeycomb or higher to use ActionBar APIs
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
// Show the Up button in the action bar.
getActionBar().setDisplayHomeAsUpEnabled(true);
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}
MyFirstApp Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myfirstapp"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.myfirstapp.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.myfirstapp.DisplayMessageActivity"
android:label="#string/title_activity_display_message"
android:parentActivityName="com.example.myfirstapp.MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.myfirstapp.MainActivity" />
</activity>
</application>
</manifest>
Thank you for your help

I believe the problem is
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
before onCreate(). Intent needs a Context which isn't available until the Activity has been created. Remove those lines since you already have it in onCreate().
Also, when it crashes, post your full logcat because it will tell us, usually, exactly where and what the problem is.

Cannot pass a search variable in Android search widget

I cannot pass my search query which is sent from my MainActivity.java to my SearchResultsActivity.java, with a search widget as described on the official guide.
However, I don't want my search widget to be set on the actionbar.
I got no error. My only wish is to get my query displayed thanks to "Log.v".
But the official guide seems only to explain how to call the another activity when we got a search widget inside the actionbar, which isn't our case here.
How to retrieve the variable query in my MainActivity.java ?
MainActivity.java:
package com.example.fidbacks_search;
import android.os.Bundle;
import android.app.Activity;
import android.app.SearchManager;
import android.content.Context;
import android.view.Menu;
import android.widget.SearchView;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
SearchResultsActivity.java
package com.example.fidbacks_search;
import android.os.Bundle;
import android.app.Activity;
import android.app.SearchManager;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
public class SearchResultsActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search_results);
Log.v("QUERY", "this isn t even being displayed when the search button is pressed");
// Get the intent, verify the action and get the query
Intent intent = getIntent();
if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
String query = intent.getStringExtra(SearchManager.QUERY);
Log.v("QUERY", query.toString());
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.search_results, menu);
return true;
}
}
Searchable.xml
<?xml version="1.0" encoding="utf-8"?>
<searchable xmlns:android="http://schemas.android.com/apk/res/android"
android:label="test"
android:hint="test2" >
</searchable>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.fidbacks_search"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.fidbacks_search.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.fidbacks_search.SearchResultsActivity"
android:label="#string/title_activity_search_results"
android:launchMode="singleTop">
<intent-filter>
<action android:name="android.intent.action.SEARCH" />
</intent-filter>
<meta-data android:name="android.app.searchable"
android:resource="#xml/searchable"/>
</activity>
</application>
</manifest>
layout/activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<SearchView
android:id="#+id/searchfield"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginTop="144dp"
android:iconifiedByDefault="false" >
</SearchView>
</RelativeLayout>

I'm not sure exactly how you want it done, but I've used SearchView recently and to get what you want, I would simply do the following.
In your activity, add to onCreate something like:
searchView = (SearchView) findViewById(R.id.searchfield);
SearchManager searchManager = (SearchManager) getActivity().getSystemService(Context.SEARCH_SERVICE);
searchView.setQueryHint("Enter query here");
searchView.setOnQueryTextListener(this);
Then have your current activity implement SearchView.OnQueryTextListener's two methods; the one you are looking for is onQueryTextSubmit. Here, use the query that's passed to it and call your SearchResultsActivity.
Intent intent = new Intent(this, SearchResultsActivity.class);
intent.putExtra("query",query);
startActivity(intent);
Then have your SearchResultsActivity get the query in `onCreate':
query = getIntent().getStringExtra("query");
Then, use the query and do whatever you want with it.

Helloworld Doesn't run on Emulator

Okay, this is really ticking me off. I ran it on both my emulator and on an android device. The code does NOT display "Helloworld, Android -mykong.com". I start the app, find it on the emulator, click on it, and it goes to interface of the app. However, it is just a blank screen! This error is not an issue of me finding the app, its not with the emulator or the android phone, the issue has to lie either in the code or in the way the code is structured/built. I know the the helloworld code is 100% correct because its from a reputable tutorial site. These are my three pairs of code. Please help, I am in desperate need!
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test123"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.test123.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
MainActivity.java
package com.example.test123;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void activity()
{
Intent helloWorld = new Intent(getApplicationContext(), HelloWorldjavaactivity.class );
startActivity( helloWorld );
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
HelloWorldjavaactivity.java
package com.example.test123;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class HelloWorldjavaactivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView text = new TextView(this);
text.setText("Hello World, Android - mkyong.com");
setContentView(text);
}
}
Activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="35dp"
android:layout_marginTop="57dp"
android:text=""
/>
</RelativeLayout>

You're not starting the HelloWorldjavaactivity.java activity. You need something like the following in your MainActivity:
Intent helloWorld = new Intent(getApplicationContext(), HelloWorldjavaactivity.class );
startActivity( helloWorld );
Of course, you need that code to be triggered by some even, a button press for example.
It would be easier to just eliminate the second activity (since your MainActivity isn't doing anything anyway) and put the code in your MainActivity instead. You'll also need to edit the layout for your MainActivity so that it includes the appropriate views.