Develop Reference

opening video in new activity

I am trying to change the main activity in android to another activity and playing a video in the new activity. but, even I changed in the manifest the main activity, it didn't show me the video when I'm starting the app. I tried to Check in the Logcat if the activity is still launched, and i didn't see any message.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mta2223">
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.MTA2223">
<activity
android:name=".Entering"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".ActivityShowingPlayers"
android:exported="false" />
<activity
android:name=".MainActivity"
android:exported="true">
</activity>
</application>
</manifest>
The new activity
package com.example.mta2223;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.widget.MediaController;
import android.widget.VideoView;
public class Entering extends AppCompatActivity {
VideoView videoView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_entering);
videoView= (VideoView) findViewById(R.id.videoV);
videoView.setVideoPath("res/raw/intrologo.3gp");
videoView.start();
while (videoView.isPlaying()){
Log.d("HEy","hey");
}
videoView.stopPlayback();
Intent i = new Intent(this,MainActivity.class);
startActivity(i);
finish();
}
}

Try this
In this code get video path from raw folder
String path = "android.resource://com.example.mta2223" + "/" + R.raw.intrologo;
videoView.setVideoPath(path);
videoView.start();

ActivityNotFoundException: Unable to find explicit activity class {co.edu.unimagdalena.projecto/co.edu.unimagdalena.projecto.informacion2}

i have one package with two class
MainActivity:
package co.edu.unimagdalena.projecto;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity implements OnClickListener {
String[] info;
private EditText nombre;
private EditText apellido;
private EditText email;
private EditText telefono;
private Button enviar;
final static String INFO = "co.edu.unimagdalena.projecto.informacion2";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
nombre=(EditText)findViewById(R.id.EditTextNombre);
apellido=(EditText)findViewById(R.id.EditTextApellidos);
email=(EditText)findViewById(R.id.EditTextCorreo);
telefono=(EditText)findViewById(R.id.EditTextTelefono);
enviar = (Button)findViewById(R.id.BtnEnviar);
enviar.setOnClickListener(this);
info=new String[4];
}
public void onClick (View v){
Intent intent = new Intent (this, informacion2.class);
intent.setClassName("co.edu.unimagdalena.projecto","co.edu.unimagdalena.projecto.informacion2");
startActivity(intent);
}
public void pasarActidadInfo (View v){
info [0] = nombre.getText().toString();
info [1] = apellido.getText().toString();
info [2] = email.getText().toString();
info [3] = telefono.getText().toString();
Intent act = new Intent (this, informacion2.class);
act.putExtra(INFO, info);
startActivity(act);
}
and other class call it informacion2:
package co.edu.unimagdalena.projecto;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.widget.TextView;
import co.edu.unimagdalena.projecto.MainActivity;
public class informacion2 extends Activity {
String [] info;
TextView nombre,apellido,email,telefono;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.informacion2);
nombre = (TextView) findViewById(R.id.mostrarNombre);
apellido= (TextView) findViewById(R.id.mostrarApellido);
email = (TextView) findViewById(R.id.mostrarEmail);
telefono = (TextView) findViewById(R.id.mostrarTelefono);
Intent men = getIntent();
info = men.getStringArrayExtra(MainActivity.INFO);
nombre.setText(info[0]);
apellido.setText(info[1]);
email.setText(info[2]);
telefono.setText(info[3]);
}
}
and this is the AndroidManifest.xml file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="co.edu.unimagdalena.projecto">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<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>
</application>
<activity
android:name=".informacion2"
android:label="#string/app_name">
</activity>
</manifest>
**I already trying everything and the error is not corrected, i am new in android studio
I can fix the error but now android studio give me this error
java.lang.RuntimeException: Unable to start activity ComponentInfo{co.edu.unimagdalena.projecto/co.edu.unimagdalena.projecto.informacion2}: java.lang.NullPointerException: Attempt to read from null array**

Try including other activity inside application in manifest file like this
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<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=".informacion2"
android:label="#string/app_name">
</activity>
</application>

setClassName takes a Package Context as first param setClassName(Context packageContext, String className):
In Android manifest
<activity android:name="co.edu.unimagdalena.projecto.informacion2">
And while starting the activity from your main activity
intent.setClassName("co.edu.unimagdalena.projecto","co.edu.unimagdalena.projecto.informacion2");

You are getting NullPointerException inside second activity, when you try to get values of Array. And you are filling array inside pasarActidadInfo method of first activity. The problem is that you are not calling pasarActidadInfo from anywhere after filling array in your first activity. So,your array would be null.
Try calling pasarActidadInfo method when you want to start new activity.
May be in onClick of button.

Always declare all android components (activities, service, receivers) inside the application tag / block and other configurations will be defined outside of application tag/block and inside manifest tag / block in Androidmanifest.xml.
Copy and paste this code in your manifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="co.edu.unimagdalena.projecto">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<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=".informacion2"
android:label="#string/app_name">
</activity>
</application>
</manifest>

Android app suddenly stops

I am learning the basics of android programming. Now I have made a Life Cycle test. The list activity works fine, but when I attempt to open the Life Cycle test, the app stops and closes. I have got the same problem on several devices. These are my codes:
(Manifest)
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.badlogic.androidgames"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".AndroidBasicsStarter"
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>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>
</manifest>
(AndroidBasicsStarter.java)
package com.badlogic.androidgames;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class AndroidBasicsStarter extends ListActivity {
String tests[] = { "LifeCycleTest", "SingleTouchTest", "MultiTouchTest", "KeyTest",
"AccelerometerTest", "AssetsTest", "ExternalStorageTest", "SoundPoolTest",
"MediaPlayerTest", "FullScreenTest", "RenderViewTest", "ShapeTest", "BitmapTest",
"FontTest", "SurfaceViewTest"
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, tests));
}
#Override
protected void onListItemClick(ListView list, View view, int position, long id) {
super.onListItemClick(list, view, position, id);
String testName = tests[position];
try {
Class clazz = Class
.forName("com.badlogic.androidgames." + testName);
Intent intent = new Intent(this, clazz);
startActivity(intent);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
(LifeCycleTest.java)
package com.badlogic.androidgames;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
public class LifeCycleTest extends Activity {
StringBuilder builder = new StringBuilder();
TextView textView;
private void log(String text) {
Log.d("LifeCycleTest", text);
builder.append(text);
builder.append('\n');
textView.setText(builder.toString());
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
textView = new TextView(this);
textView.setText(builder.toString());
setContentView(textView);
log("created");
}
#Override
protected void onResume() {
super.onResume();
log("resumed");
}
#Override
protected void onPause() {
super.onPause();
log("paused");
if (isFinishing()) {
log("finishing");
}
}
}
I use Eclipse on Windows 7. Thank you in advance!

Add your LifeCycleTest activity in AndroidManifest.xml
<activity
android:name=".LifeCycleTest"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
</intent-filter>
</activity>

Include both your activities inside your Manifest file. It should look something like this.
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".AndroidBasicsStarter"
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=".LifeCycleTest"
android:label="#string/app_name" >
</activity>
</application>

WebView reload after connection recovered?

[SOLVED] [FIXED CODE BELOW]
It is a small app with a webview, i want to reload this when connection to internet is back. I open the app (with internet connected) and it shows the web (google.com.ar), when I disconnect WiFi and 3G if I navigate on the web it show error message, it is ok, but if I reconnect WiFi the app crashes. What is the problem? I think is in the BroadReceiver, in the manifest i have android.net.wifi.STATE_CHANGE and android.net.conn.CONNECTIVITY_CHANGE.
Thanks.
MainActivity.java
package com.example.app;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.os.StrictMode;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends ActionBarActivity {
static WebView myWebView;
#Override
protected void onCreate(Bundle savedInstanceState) {
StrictMode.enableDefaults();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myWebView = (WebView) findViewById(R.id.webView);
myWebView.loadUrl("http://google.com.ar");
myWebView.setWebViewClient(new WebViewClient() );
}
}
ConnectionBroadReceiver.java
package com.example.app;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
public class ConnectionBroadReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
ConnectivityManager cm = (ConnectivityManager)
context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()) {
MainActivity.myWebView.reload();
} else {
}
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.app"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="19"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme"
android:screenOrientation="landscape" android:configChanges="orientation|keyboardHidden">
<activity
android:name="com.example.app.MainActivity"
android:label="#string/app_name"
android:screenOrientation="landscape" android:configChanges="orientation|keyboardHidden">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver
android:name="com.example.app.ConnectionBroadReceiver">
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
</intent-filter>
</receiver>
</application>
</manifest>

Why do I get a syntax error on line 1?

I'm trying to get this to open an url when the icon is selected/clicked, but I get Syntax error on tokens, delete these tokens on the line String url =
String url = "http://www.google.co.uk/";
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse(url));
startActivity(i);
Manifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.openurl"
android:versionCode="1"
android:versionName="1.0" >
<application>
<activity android:name="OpenURL" 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>
I've now got a bit further on this one but when I load the apk file the icon opens the browser with 2 windows - blank and the url. I;m also unable to use the back button to close the browser - it keeps opening the url. How can I correct these issues?
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myapp"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="14" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name">
<activity
android:name="com.example.myapp.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>
package com.example.myapp;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String url = "http://www.google.co.uk";
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse(url));
startActivity(i);
}
}
Many thanks again!

This
String url = "http://www.google.co.uk/";
can never be the first line of a java file.
You file need a structure like:
package a.b.c; // optional
import java.util.List; // optional
public class ClassName { // mandatory
// your code
} // mandatory
If this fixes your error, you should consider reading a Java tutorial.

First of all add the permission for internet in your manifest:
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
then your main should be like this:
public class Main extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.yourmainlayout);
Button button = (Button) findViewById(R.id.yourbuttonid);
button.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
String url = "http://www.google.co.uk/";
Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
startActivity(i);
}});
}
}