Develop Reference

using of intent for linking activities

I want to link my two activites by clicking on a button i have written the following code
public class IHBCAPTUREActivity extends Activity implements OnClickListener {
/** Called when the activity is first created. */
ImageView iv;
TextView tx;
Button b1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
iv=(ImageView)findViewById(R.id.imageView1);
tx=(TextView)findViewById(R.id.textView1);
b1 = (Button) findViewById(R.id.button1);
b1.setOnClickListener(this);
}
#Override
public void onClick(View v) {
Intent calIntent;
**calIntent = new Intent(IHBCAPTUREActivity.this, LoginActivity.class);**
startActivity(calIntent);
}
}
error cumes in this line
calIntent = new Intent(IHBCAPTUREActivity.this, LoginActivity.class);
for LoginActivity.class that
LoginActivity cannot be resolved to a type . How to solve it?

here is the simple code how you can load one activity to another,
i have created two activities like this
FirstActivity.java
package com.rdc;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class FirstActivity extends Activity implements OnClickListener {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.first);
Button btnload = (Button) findViewById(R.id.btn);
btnload.setOnClickListener(this);
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent i = new Intent(this, SecondActivity.class);
startActivity(i);
}
}
SecondActivity.java
package com.rdc;
import android.app.Activity;
import android.os.Bundle;
public class SecondActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
}
}
and my manifest file is
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.rdc"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".FirstActivity"
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=".SecondActivity"
android:label="#string/app_name">
<intent-filter>
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
try to implement this in your app and let me know if still any doubt is there.

Check whether you have declared LoginActivity in manifest file as:
<activity
android:name="your.package-name.LoginActivity" >
</activity>

You don't have anything wrong in code.
Its know issue that occurs randomly.
solution is to set the target to other API level in project->properties->android, then set it back.then clean you project once.
I think this will refresh the .classpath or some other files, not sure, but it works.

Unable to Override OnCreate of an Activity [closed]

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Closed 10 years ago.
I have 2 Activities, one which is MainActivity and the other, ReadActivity.
Whenever I started ReadActivity from MainActivity, the Activity started but it shows nothing, just the android:label value in the Manifest file.
As I was investigating, I tried putting a Log in ReadActivity but I noticed that the OnCreate method isn't called as I forgot to override the method but when I put the "#Override" above the OnCreate method I get the followong error:
"The method OnCreate(Bundle) of type ReadActivity must override or implement a supertype method".
I don't get what's wrong with this line, I've crossed checked it so many times, compared the codes with other application's code but I just can't seem to override it. Can anyone help me? Below are the codes of my project.
MainActivity
package com.rangga.elearning.ngaji;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View.OnClickListener;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity{
/** Called when the activity is first created. */
TextView txtLogo, txtVersion;
Button btnRead, btnIndex, btnAbout;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
//Typeface font = Typeface.createFromAsset(getAssets(), "assets/Schoolbell.ttf");
txtLogo = (TextView) findViewById(R.id.txtLogo);
txtVersion = (TextView) findViewById(R.id.txtVersion);
btnRead = (Button) findViewById(R.id.btnRead);
btnIndex = (Button) findViewById(R.id.btnIndex);
btnAbout = (Button) findViewById(R.id.btnAbout);
/* txtLogo.setTypeface(font);
txtVersion.setTypeface(font);
btnRead.setTypeface(font);
btnIndex.setTypeface(font);
btnAbout.setTypeface(font); */
btnRead.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
callIntent();
}
});
}
public void callIntent(){
Intent i = new Intent(this, ReadActivity.class);
startActivity(i);
}
}
ReadActivity
package com.rangga.elearning.ngaji;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.view.WindowManager;
public class ReadActivity extends Activity{
private static String TAG = "ReadActivity";
#Override
public void OnCreate(Bundle savedInstanceState){
Log.i(TAG, "ReadActivity dimulai");
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.read);
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.rangga.elearning.ngaji"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="7"
android:targetSdkVersion="7"
android:maxSdkVersion="8" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:screenOrientation="landscape" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".ReadActivity"
android:label="Baca"
android:screenOrientation="landscape">
</activity>
</application>
</manifest>
Thank you.

onCreate() not OnCreate() . Besides, your manifest doesn't contain Intent information for your ReadActivity.

Using intents to switch activities

I am reading a android book for beginners, and while following on of the chapters I ran into a problem. The chapter is teaching about intents. I right now I have 2 layouts: main.xml, and digital_clock.xml. And in the AndroidManifest I have these lines of code:
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:label="#string/app_name"
android:name=".Chapter11Activity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".DigitalClockActivity" >
</activity>
</application>
Also I have the two Activity classes that correspond to the layouts:
Chapter11Activity:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class Chapter11Activity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button a2 = (Button)findViewById(R.id.button1);
a2.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent myIntent = new Intent(v.getContext(), DigitalClockActivity.class);
startActivityForResult(myIntent, 0);
}
});
}
}
DigitalClockActivity:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class DigitalClockActivity extends Activity {
public void OnCreate(Bundle sIS) {
super.onCreate(sIS);
setContentView(R.layout.digital_clock);
Button a1 = (Button) findViewById(R.id.button01);
a1.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent replyIntent = new Intent();
setResult(RESULT_OK, replyIntent);
finish();
}
});
}
}
When I run the app on my phone and switch to the second activity it shows nothing at all. Am I defining something wrong in the AndroidManifest? The application seems very straight forward, but it is not working. I have check over to make sure I didn't type anything wrong. Is it because I am running a android 2.3.3 phone and using the 1.5 sdk, and something is not backwards compatible? Any answers are appreciated!
~Andrew

Method name in second activity should be onCreate not OnCreate.
To prevent typos like this in the future use #Override on methods that you are overriding:
#Override
public void OnCreate(Bundle sIS) {
// code here
}
Then if you make a typo, the compiler will tell about it.

getting exception when starting new activity on an android

i have read a lot about this but didnt come up with a solution.
this is my first android project.
i am trying yo open an activity from my main activity.
i have doubled check the names and the configuration files, but the startactivity() procedure fails.
debbuger shows runtime errror.
as u will c, the startactivity is called upon onclick event.
i am really stuck here dont know what else to do.
thanks a lot!
* this is the main activity **
package com.example.helloandroid;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class HelloworldActivity extends Activity {
/** Called when the activity is first created. */
private OnClickListener gtScoringListener = new OnClickListener() {
public void onClick(View v) {
Intent mintent = new Intent(HelloworldActivity.this ,imgScoring.class);
startActivity(mintent);
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button)findViewById(R.id.button1);
button.setOnClickListener(gtScoringListener);
}
}
* this is the target activity: *
package com.example.helloandroid;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class imgScoring extends Activity {
private OnClickListener backBtnListener = new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(imgScoring.this, HelloworldActivity.class);
startActivity(intent);
}
};
private OnClickListener scoreBtnListener = new OnClickListener() {
public void onClick(View v){
TextView tv = (TextView)findViewById(R.id.editText1);
tv.setText(((Button)v).getText());
}
};
/** Called when the activity is first created. */
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Button button = (Button)findViewById(R.id.button1);
button.setOnClickListener(scoreBtnListener);
button = (Button)findViewById(R.id.Button01);
button.setOnClickListener(scoreBtnListener);
button = (Button)findViewById(R.id.Button03);
button.setOnClickListener(scoreBtnListener);
button = (Button)findViewById(R.id.Button02);
button.setOnClickListener(scoreBtnListener);
button = (Button)findViewById(R.id.Button04);
button.setOnClickListener(scoreBtnListener);
button = (Button)findViewById(R.id.button3);
button.setOnClickListener(backBtnListener);
setContentView(R.layout.imgscoring);
}
}
this is the androidmanifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.helloandroid"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="12" />
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".imgScoring"></activity>
<activity android:name=".HelloworldActivity"
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>

You should've posted the stacktrace, but I assume the error is on this line in your target activity:
button.setOnClickListener(scoreBtnListener);
This will give you a NULL:
Button button = (Button)findViewById(R.id.button1);
because you haven't set a contentview in THAT activity, so there is nothing for findViewById() to return. You'll get a nullpointer when calling that setOnclickLIstener()

Try change class name from imgScoring to ImgScoring everywhere. Java is not allowing class name to start from small letter ;-)
And place setContentView(R.layout.imgscoring); just after your super.onCreate();

Android execution error in AVD

an anyone look at this simple code (?) and tell me what's wrong please?
I'm a complete beginner to android development and I don't understand why my application doesn't even start. I get an unexpected error.. : (
Here it is:
package applicationTest.ppr.com;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
public class MainClass extends Activity {
/** Called when the activity is first created. */
/*Global vars*/
public static LinearLayout lila;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
lila = (LinearLayout) findViewById(R.id.lilay);
setContentView(lila);
}
public void Shortoast(){new Game(this);}
public static LinearLayout returnLayout(){return lila;}
}
The program doesn't even launch, and I think it might have something to do with how I handle the LinearLayout and setContentView();
anyway thanks very much in advance!

Suggestion: keep it as simple as possible until you fix the issue!
Then you can concentrate on your business logic.
package applicationTest.ppr.com;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
public class MainClass extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.id.lilay);
}
}
Also, is your main activity mapped in the Android manifest?
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name="MainClass"
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>
--EDIT--
Do you have the lilay.xml file in your res/layout folder?