I'm trying to send content through Intent (I think this is the reason of my error) and I constantly get ActivityNotFoundException.
Here's the class which is sending data to Tab1.class (String called temperature)
I found similar question on stack where someone wrote that problem is caused by instantiating the intent before the activity has gone through its life cycle methods but I'm not sure if it is a problem and what should I do to fix it
public class ChooseLayout extends AppCompatActivity implements View.OnClickListener {
EditText editText;
Button button;
Weather weather;
Parser parser = new Parser();
SharedPreferences sharedPreferences;
String temperature, preassure,WindSpeed,WindDirection,Humidity,ViewDescription;
boolean isChecked = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.choose_layout);
editText = (EditText) findViewById(R.id.editText);
button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (!isOnline()) {
Toast.makeText(getApplicationContext(), "Cannot connect to network, data will be restore from file with last downloaded data...", Toast.LENGTH_LONG).show();
} else {
Thread t = new Thread(new Runnable() {
#Override
public void run() {
try {
weather = parser.getWeatherForLocation(editText.getText() + "");
runOnUiThread(new Runnable() {
#Override
public void run() {
editText.setText(weather.getCity() + ", " + weather.getCountry());
temperature = weather.getTemperature();
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
});
t.start();
}
Intent intent = new Intent(getApplicationContext(),Tab1.class);
intent.putExtra("temperature", temperature);
startActivity(intent);
}
});
sharedPreferences = getSharedPreferences("file_name", MODE_PRIVATE);
}
I have declared this activity in AndroidManifest.xml :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.chirag.slidingtabsusingviewpager">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<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/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".ChooseLayout"></activity>
</application>
</manifest>
You can either add or replace fragment in your activity.
Then do this in your activity to add fragment:
FragmentManager manager = getSupportFragmentManager();
Tab1 tab1 = new Tab1();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(android.R.id.content, tab1);
transaction.commit();
Or to replace fragment do this:
FragmentManager manager = getSupportFragmentManager();
Tab1 tab1 = new Tab1();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(android.R.id.content, tab1);
transaction.commit();
To pass data from fragment you can use Bundle as,
Bundle bundle = new Bundle();
bundle.putString("your_tag", your_string);
FragmentManager manager = getSupportFragmentManager();
Tab1 tab1 = new Tab1();
tab1.setArguments(bundle);
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(android.R.id.content, tab1);
transaction.commit();
To know about more fragment-transaction check this https://developer.android.com/reference/android/app/FragmentTransaction.html
Related
I created one app with two activities when I run app It opens first launcher activity In this activity I added textViewon clicking this textViewsecond activity is opened,
At the second activity again I added one textView on clicking that textView I expected to launch my first activity(Launcer activity) but this doesn't happens? Why? My Manifest file is as follows
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.adbs.abs.dhanagarmaza" >
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<activity
android:name=".LoginRegi"
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=".Register"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar" >
<intent-filter>
<action android:name="com.adbs.abs.REGISTER" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
My LoginRegi(Second activity java file 'DEFAULT activity')
protected void onCreate(Bundle registerBundle) {
super.onCreate(registerBundle);
setContentView(R.layout.register);
// If user wants to login then on click "Login Me" textView open activity(LoginRegi.xml)
loginMe = (TextView)findViewById(R.id.tvLoginMe);
loginMe.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent openLoginRegi = new Intent("android.intent.action.MAIN");
startActivity(openLoginRegi);
}
});
}
and LoginRegi.java (First activity 'LAUNCHER activity')
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login_regi);
// On click signup textView => Open activity (register.xml)
signUp = (TextView)findViewById(R.id.tvSignUp);
signUp.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent openRegister = new Intent("com.adbs.abs.REGISTER");
startActivity(openRegister);
}
});
}
Activity 1:-
public class MainActivity extends Activity {
TextView tvOne;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvOne=(TextView)findViewById(R.id.tvOne);
tvOne.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent=new Intent(getApplicationContext(),Main2Activity.class);
startActivity(intent);
}
});
}
}
Activity 2:-
public class Main2Activity extends Activity {
TextView tvTwo;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
tvTwo=(TextView)findViewById(R.id.tvTwo);
tvTwo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent=new Intent(getApplicationContext(),MainActivity.class);
startActivity(intent);
}
});
}
}
Intent i =new Intent(this,MainActivity.class);
startActivity(i);
you can post your code so we can get exact problem because ..
by finish(); you can get your prevous activity back either you can do it by Intent
My LoginRegi(Second activity java file 'DEFAULT activity')
protected void onCreate(Bundle registerBundle) {
super.onCreate(registerBundle);
setContentView(R.layout.register);
// If user wants to login then on click "Login Me" textView open activity(LoginRegi.xml)
loginMe = (TextView)findViewById(R.id.tvLoginMe);
loginMe.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent openLoginRegi = new Intent(Register.this,LoginRegi.class);
startActivity(openLoginRegi);
}
});
}
and LoginRegi.java (First activity 'LAUNCHER activity')
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login_regi);
// On click signup textView => Open activity (register.xml)
signUp = (TextView)findViewById(R.id.tvSignUp);
signUp.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent openRegister = new Intent(LoginRegi.this,Register.class);
startActivity(openRegister);
}
});
}
I am creating an android app and when I go to debug it on my samsung galaxy the Splash activity loads first,as it should, but after that the app crashes/stops right after doing the "Splash" activity. It doesn't go to the "MainActivity" activity after the thread sleeps for 5 seconds. Does anyone know what might be causing the problem? Plus after I tried debugging the app and loaded it onto my phone the app isn't even showing up. I am using Eclipse by the way. It shows the app in my application manager on my phone but it doesn't show the icon in my app screen.
Here is my Splash.java:
package com.example.mihirsandroidapp;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class Splash extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.splash);
Thread timer = new Thread(){
public void run(){
try{
sleep(5000);
} catch (InterruptedException e){
e.printStackTrace();
}finally{
Intent openMainActivity = new Intent("com.example.mihirandroidsapp.MAINACTIVITY");
startActivity(openMainActivity);
}
}
};
timer.start();
}
#Override
protected void onPause() {
super.onPause();
finish();
}
}
Here is my Manifest:
<?xml version="1.0" encoding="utf-8"?>
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<application
android:debuggable="true"
android:allowBackup="true"
android:icon="#drawable/cartooncat"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".Splash"
android:label="#string/app_name" >
<intent-filter>
<action android:name="com.example.mihirsandroidapp.SPLASH" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="com.example.mihirsandroidapp.MAINACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
And here is my main activity which should start after the splash screen:
package com.example.mihirsandroidapp;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
int counter;
Button add, sub;
TextView display;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
counter = 0;
add = (Button) findViewById(R.id.bAdd);
sub = (Button) findViewById(R.id.bSub);
display = (TextView) findViewById(R.id.tvDisplay);
add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
counter += 1;
display.setText("Total is " + counter);
}
});
sub.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
counter -= 1;
display.setText("Total is " + counter);
}
});
}
}
Oh.. Where do I start.. Let's go through all of the issues:
1) Fix your manifest. Definitely not the right way to declare your activities. Here is what it should look like:
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<application
android:debuggable="true"
android:allowBackup="true"
android:icon="#drawable/cartooncat"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".Splash"
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=".MainActivity"
android:label="#string/app_name" >
</activity>
</application>
2) Now let's fix the way you start your activity:
Intent openMainActivity = new Intent(Splash.this, MainActivity.class);
3) Don't call finish() in onPause() - you break native activity lifecycle flow. Call finish() right after you start new activity:
Intent openMainActivity = new Intent(Splash.this, MainActivity.class);
startActivity(openMainActivity);
finish();
4) Instead of creating separate thread, just a create a Handler and post Runnable there with 5 seconds delay:
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
//this will be called after 5 seconds delay
}
}, 5000);
Here is entire file put together:
public class Splash extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.splash);
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
Intent openMainActivity = new Intent(Splash.this, MainActivity.class);
startActivity(openMainActivity);
finish();
}
}, 5000);
}
If it doesn't help - we definitely need to look at logcat output...
A simple way to achieve this if one is ready to compromise on drawing performance is to define custom theme with splash image that one wants to use as window background and use this custom theme as application theme
styles.xml
<resources>
<style name="CustomTheme" parent="android:Theme">
<item name="android:windowBackground">#drawable/background_image</item>
<item name="android:windowNoTitle">true</item>
</style>
</resources>
AndroidManifest.xml
<application
android:debuggable="true"
android:icon="#drawable/icon"
android:theme="#style/CustomTheme"
android:label="#string/app_name">
...
</application>
This would use the #drawable/background_image as the window.background. As a result if the activities has transparent background then #drawable/background_image will be visible as activities background. One can avoid this by setting appropriate color or drawable in onCreate of every activity programatically as
public void onCreate(){
super.onCreate(savedInstanceState);
setContentView(R.layout.layoutResID);
activity.getWindow().setBackgroundDrawableResource(R.color.window_bg);
}
Check this for more information
All what you need for a splash screen
SplashActivity.java
public class SplashActivity extends AppCompatActivity {
private final int SPLASH_DISPLAY_DURATION = 1000;
#Override
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
new Handler().postDelayed(new Runnable(){
#Override
public void run() {
Intent mainIntent = new Intent(SplashActivity.this,MainActivity.class);
SplashActivity.this.startActivity(mainIntent);
SplashActivity.this.finish();
}
}, SPLASH_DISPLAY_DURATION);
}}
In drawables create this bg_splash.xml
<?xml version="1.0" encoding="utf-8"?><layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:drawable="#color/app_color"/>
<item>
<bitmap
android:gravity="center"
android:src="#drawable/ic_in_app_logo_big"/>
</item></layer-list>
In styles.xml create a custom theme
<style name="SplashTheme" parent="Theme.AppCompat.NoActionBar">
<item name="android:windowBackground">#drawable/bg_splash</item>
</style>
and finally in AndroidManifest.xml specify the theme to your activity
<activity
android:name=".activities.SplashActivity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:theme="#style/SplashTheme">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Cheers.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Thread th = new Thread(new Runnable() { /*create a new thread */
#Override
public void run() { /*
* The purpose of this thread is to
* navigate from one class to another
* after some time
*/
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
/*
* We are creating this new thread because we don’t
* want our main thread to stop working for that
* time as our android stop working and some time
* application will crashes
*/
e.printStackTrace();
}
finally {
Intent i = new Intent(MainActivity.this,
Splash_Class.class);
startActivity(i);
finish();
}
}
});
th.start(); // start the thread
}
http://www.codehubb.com/android_splash_screen
I have added splash screen by using following code:
public class SplashActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.splash_layout);
initConstatnts();// method for intilizing any constants
new Thread(new Runnable() {
#Override
public void run() {
if (!isFinishing()) // checking activity is finishing or not
{
try {
Thread.sleep(3000);//delay
Intent i = new Intent(getBaseContext(),
HomeActivity.class);
startActivity(i);
finish();
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
}).start();
}
private void initConstatnts() {
}
}
Flow the below steps to Create your own splash screen
Create Activity1 and XML file
Design the XML file and put the welcome message
Crete Activity2 and XML file.
Start the Activity1
Start a Thread in Activity1 and sleep for 5 seconds
Start Activity2 from the Thread
There is nothing called readymade splash screen in Android . we can achieve that using above steps.
In a single line, start Activity1 wait for 5 sec then start Activity2.
So user will feel that first screen is splash screen.
You can download the complete code from below link
http://javaant.com/splash-screen-android/#.VwzHz5N96Hs
i have faced the same problem.... i think you code is perfect for the app
u just try with this in the Intent Creation in your splash activity class
Intent openMainActivity = new Intent("android.intent.action.MAIN");//MAIN is the that u want to start
//next after the current Activity
Basically I'm just trying to run a class which is called NotificationReceiverActivity from another Activity class, but nothing shows up on the screen when I click on the button to run the activity class, I feel like I'm being a total noob on the xml part of the code and here is the AndroidManifest.xml ;
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="de.vogella.android.notificationmanager"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="16"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="de.vogella.android.notificationmanager.CreateNotificationActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="#string/app_name"
android:theme="#style/FullscreenTheme" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="de.vogella.android.notificationmanager.NotificationReceiverActivity"
android:label="#string/app_name"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
The main activity which is CreateNotificationActivity class, works and turns on flawlessly.
Java code for the main activity;
public class CreateNotificationActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void createNotification(View view) {
// Prepare intent which is triggered if the
// notification is selected
Intent intent = new Intent(this, NotificationReceiverActivity.class);
PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);
// Build notification
// Actions are just fake
Notification noti = new Notification.Builder(this)
.setContentTitle("New mail from " + "test#gmail.com")
.setContentText("Subject").setSmallIcon(R.drawable.icon)
.setContentIntent(pIntent)
.addAction(R.drawable.ic_launcher, "Call", pIntent)
.addAction(R.drawable.ic_launcher, "More", pIntent)
.addAction(R.drawable.ic_launcher, "And more", pIntent).build();
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
// hide the notification after its selected
noti.flags |= Notification.FLAG_ONGOING_EVENT;
notificationManager.notify(0, noti);
}
}
And the NotificationReceiverActivity class;
public class NotificationReceiverActivity extends Activity implements OnClickListener {
private final String CLASSNAME = getClass().getSimpleName();
Camera cam = null;
ImageButton ib1;
Parameters para;
PowerManager pm;
WakeLock wl;
#Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
wl = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK, "whatever");
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
wl.acquire();
initialize();
ib1.setOnClickListener(this);
Log.i(CLASSNAME, "CREATING NOW"+cam);
}
private void initialize() {
// TODO Auto-generated method stub
ib1 = (ImageButton) findViewById(R.id.ib2);
}
public void onClick(View v) {
// TODO Auto-generated method stub
if (cam == null) {
cam = Camera.open();
para = cam.getParameters();
para.setFlashMode(Parameters.FLASH_MODE_TORCH);
cam.setParameters(para);
Log.i(CLASSNAME, "AA"+cam);
} else {
para.setFlashMode(Parameters.FLASH_MODE_OFF);
cam.setParameters(para);
cam.release();
cam = null;
Log.i(CLASSNAME, "BB"+cam);
}
}
#Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
wl.release();
cam=cam;
finish();
}
#Override
protected void onDestroy() {
super.onDestroy();
cam=cam;
}
}
And the top 4 lines of the log cat;
01-31 06:11:10.582: E/AndroidRuntime(29533): FATAL EXCEPTION: main
01-31 06:11:10.582: E/AndroidRuntime(29533): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.vogella.android.notificationmanager/de.vogella.android.notificationmanager.NotificationReceiverActivity}: java.lang.SecurityException: Neither user 10181 nor current process has android.permission.WAKE_LOCK.
01-31 06:11:10.582: E/AndroidRuntime(29533): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
01-31 06:11:10.582: E/AndroidRuntime(29533): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
Remove the intent filter from your NotificationReceiverActivity.
to use a button to start NotificationReceiverActivity from you CreateNotificationActivity you have to assign a clicklistener to that button in you activity
This is an example of this
public class CreateNotificationActivity extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
addListenerOnButton();
}
public void addListenerOnButton() {
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent intent = new Intent(CreateNotificationActivity.this,NotificationReceiverActivity.class);
startActivity(intent);
}
});
}
}
I am trying to open another activity through Intent on Button press.
But the app crashes every time on launch.
IntentTest.java:
package com.example.intenttest;
public class IntentTest extends Activity {
Button b1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_intent_test);
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent2 = new Intent(IntentTest.this, IntentTest2.class);
startActivity(intent2);
}
});
}
}
IntentTest2.java:
package com.example.intenttest;
public class IntentTest2 extends Activity {
TextView textView1;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_intent_test2);
textView1=(TextView)findViewById(R.id.textView1);
}
}
Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.intenttest"
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.intenttest.IntentTest"
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:label="#string/app_name" android:name="com.example.intenttest.IntentTest2" />
</application>
</manifest>
Here is the LogCat where the app crashes:
12-18 11:59:59.563: W/Trace(20985): error opening trace file: No such file or directory (2)
12-18 11:59:59.623: D/AndroidRuntime(20985): Shutting down VM
12-18 11:59:59.623: W/dalvikvm(20985): threadid=1: thread exiting with uncaught exception (group=0x40c8d930)
12-18 11:59:59.633: E/AndroidRuntime(20985): FATAL EXCEPTION: main
12-18 11:59:59.633: E/AndroidRuntime(20985): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.intenttest/com.example.intenttest.IntentTest}: java.lang.NullPointerException
I cant find out what is wrong. Please help.
Because you did not initialize b1(Button)
b1 = (Button)findViewById(R.id.button_id);
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent2 = new Intent(IntentTest.this, IntentTest2.class);
startActivity(intent2);
}
});
you forgot to initialze button object in IntentTest
b1=(Button)findViewById(R.id.b1);
like this way with your button id.
Button b1 is not initialized. So it's null.
Fisrt initialize your button
Button b1 = (Button)findViewById(R.id.Buttonid);
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent2 = new Intent(IntentTest.this, IntentTest2.class);
startActivity(intent2);
}
});
else directly use like this
findViewById(R.id.Buttonid).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent2 = new Intent(IntentTest.this, IntentTest2.class);
startActivity(intent2);
}
});
You did not initialize your button b1 in IntentTest class,
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_intent_test);
b1=(Button)findViewById(R.id.your_btn_name);
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent2 = new Intent(IntentTest.this, IntentTest2.class);
startActivity(intent2);
}
});
}
Right now I am getting a force close on my android emulator.
Upon finishing this app, I will want to put a custom field in instead of just test, but for now I just want test to show up from the http activity.
Any help would be great!
MainActivity:
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.main.MESSAGE";
/*#SuppressLint("ParserError")
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}*/
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
private Button searchBtn;
#Override
protected void onCreate(Bundle savedInstance){
super.onCreate(savedInstance);
setContentView(R.layout.activity_main);
searchBtn = (Button) findViewById(R.id.button1);
searchBtn.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent intent = new Intent(null, http.class);
startActivity(intent);
}
});
}
}
Http:
public class http extends Activity {
public http(){
httpMethod();
}
public void httpMethod(){
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://api.site.com/api/");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
;
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
String test = "hello";
TextView myTextView = (TextView) findViewById(R.id.myTextView);
myTextView.setText(test);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
}
Manifest:
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.example.main.DisplayMessageActivity"/>
<activity android:name="com.example.main.http"/>
</application>
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
</manifest>
There are whole lot of issues in the code:
1) Intent intent = new Intent(null, http.class);
Use first parameter as MainActivity.class instead of null
2) httpActivity should have onCreate (or) onResume life cycle activity methods to create activity for startActivity
Not but the least, please spend some time on reading documentation and doing example programs instead of just type-in something and post on SO. By going through all your questions it is something like SO community did your app for you.
You have to initialize Intent like this
Intent intent = new Intent(MainActivity.this, http.class);
You need to pass Context as first parameter not null.
start as:
searchBtn.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent intent = new Intent(MainActivity.this, http.class);
startActivity(intent);
}
});
instead of passing null as First parameter in Intent Constructor
for more information see here
http://developer.android.com/reference/android/content/Intent.html
I trully advice you to read some Android basics beacause you have some issues in the code:
You have a null context when you're initializing the intent at the button's listener. You should have: Intent intent = new Intent(getApplicationContext(), http.class); or Intent intent = new Intent(MainActivity.this, http.class);
You need to create your ativity and set it's content. You must override at least the onCreate method.
It's not so important, but its a good practice to write code that anyone might understand instead of write code for the machine! I'm telling this because you have *activity_main* sml file where you define your main activity layout and menu. I suggest you to refractor these file names to something like main.xml, for the layout, and *main_mnu.xml*.