Develop Reference

"Error: cannot find symbol class app"

I have external package class (my custom library), which I want to include in the project. It uses Activity, but shows error as you see.
If I place this command in main project class, it works well... What to do?
Here is the code:
package com.__MyDefaultLibrary;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.LinearInterpolator;
import android.view.animation.ScaleAnimation;
import android.widget.*;
import java.io.File;
import java.util.Calendar;
//
import android.app.Activity;
import com.oceanesa.samplevideorecorder.R;
public class __MyDefaultFunctions{
public android.app.Activity actv1 = android.app.Activity;
public void Initt(){
PreferenceManager.setDefaultValues(actv1.getBaseContext(), R.xml.mypreferences, false);
}
// ========== MY CUSTOM LIBRARY =============//
//button find
public Button fvb(int id) {
return (Button) actv1.findViewById(id);
}
//message show
public void msg(String text) {
Toast.makeText(actv1.getApplicationContext(), text, Toast.LENGTH_LONG).show();
}
public View.OnClickListener optionsListener2 = new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(actv1.getBaseContext(), com.__MyDefaultLibrary.__MyDefaultPreferencesInit1.class);
actv1.startActivity(i);
}
};
}
And AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.oceanesa.samplevideorecorder"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="16"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<uses-feature
android:name="android.hardware.camera.front"
android:required="false" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:screenOrientation="landscape"
android:theme="#style/AppTheme"
>
<activity
android:name="com.oceanesa.samplevideorecorder.VideoCaptureExample"
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.__MyDefaultLibrary.__MyDefaultPreferencesInit1"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN_ACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>

Update Answer just passing context to class
public class MyClass {
private static Context mContext;
private static Activity mActivity;
public MyClass(Context c) {
mContext= c;
}
public MyClass(Activity act) {
mActivity= act;
}
public static void showToastMethod() {
// then passing context or activity to
Toast.makeText(mContext, "mymessage ", Toast.LENGTH_SHORT).show();
// or Toast.makeText(mActivity, "mymessage ", Toast.LENGTH_SHORT).show();
}
}

Finally I got it working with the help of topic: How to display a Toast message in from a class that doesn't extend Activity
Problem was in my code. There was no need to call andorid.app at all. I didnt pass Activity to my external file, from where I couldnt call anything..
I had to pass activity like this (from main project file):
public MyExternalClass myEx = new MyExternalClass(Activity);
and needed some modifications...

Unfortunately [yourapp], has stopped

I'm using intent method to make a simple app that takes you from main screen [with an enter button] to another screen which has three options. Code sourced online and seems to be error free, though my app crashes saying "Unfortunately [yourapp], has stopped" immediately after i press the button which is meant to take to the the other screen.
This is my first activity code:
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButton();
}
public void addListenerOnButton() {
final Context context = this;
button = (Button) findViewById(R.id.enterBtn);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent intent = new Intent(context, HomeActivity.class);
startActivity(intent);
}
});
}
}`
And this is my landing screen's activity code:
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
public class HomeActivity extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
}
}
I'm really stuck with this issue and any help would be much appreciated. Many thanks in advance.

Every activity needs to be added in your manifest file under application tag. This seems to be the problem in your case.

Try to post you LogCat so that we might get some more information and if you have not yet added your Activity in the manifest, this is the way of adding it (Activities go under application tag)
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.southmp3"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="#drawable/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=".HomeActivity"
android:label="#string/app_name" >
</activity>
</application>
all the Activities should be going under the application tag

I had forgotten to register my new activity on the androidmanifest.xml file. That's what sorted my app crash issue.

Same xml code, different graphic layout

I am new to android development and i tried copying an xml layout from another project, but the graphic layout of that xml seems to be different from what i am getting. I have no idea what is missing in my project that I am not getting the same layout. Please help.
this is what it looks like
!1
and this is what i get after copying the exact code.
!2
my xml file
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.aditya.contentsharer"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
android:name=".InteriorSpottingApplication"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".InteriorListActivity"
android:label="#string/title_activity_interior_list" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="android.app.Activity" />
</activity>
<activity
android:name=".NewInteriorActivity"
android:label="#string/title_activity_new_interior" >
</activity>
</application>
</manifest>
xml code
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/fragmentContainer"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
java code
package com.aditya.contentsharer;
import android.app.Activity;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import com.parse.ParseQueryAdapter;
public class InteriorListActivity extends ListActivity{
private ParseQueryAdapter<Interior> mainAdapter;
private FavoriteInteriorAdapter favoritesAdapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getListView().setClickable(false);
mainAdapter = new ParseQueryAdapter<Interior>(this, Interior.class);
mainAdapter.setTextKey("title");
mainAdapter.setImageKey("photo");
// Subclass of ParseQueryAdapter
favoritesAdapter = new FavoriteInteriorAdapter(this);
// Default view is all interiors
setListAdapter(mainAdapter);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_interior_list, menu);
return true;
}
/*
* Posting interiors and refreshing the list will be controlled from the Action
* Bar.
*/
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_refresh: {
updateinteriorList();
break;
}
case R.id.action_favorites: {
showFavorites();
break;
}
case R.id.action_new: {
newinterior();
break;
}
}
return super.onOptionsItemSelected(item);
}
private void updateinteriorList() {
mainAdapter.loadObjects();
setListAdapter(mainAdapter);
}
private void showFavorites() {
favoritesAdapter.loadObjects();
setListAdapter(favoritesAdapter);
}
private void newinterior() {
Intent i = new Intent(this, NewInteriorActivity.class);
startActivityForResult(i, 0);
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == Activity.RESULT_OK) {
// If a new post has been added, update
// the list of posts
updateinteriorList();
}
}
}

I got the solution. I removed android:theme="#style/AppTheme" from the manifest file. That worked fine for me.

I am not used to deal with ListActivities since I usually do it with a ListView in a normal activity but my first guess is that you still need to have a line like this in your onCreate() method to actually get any layout...
setContentView(R.layout.fragmentContainer);
(assuming your xml file has the same name as it's ID right?
Try putting it after the
super.onCreate(savedInstanceState);
I am not sure if it will work but try it! :)

Zbar integration into Android app

I am using the Android ADT Bundle for dev work. After reading multiple guides online I have added the package com.dm.zbar.android.scanner to my project. I have included the files CameraPreview.java, ZBarConstants.java, and ZBarScannerActivity.java in the package. Despite all this the ZBAR_SCANNER_REQUEST var in the class ScanActivity.java (created by me, but using zbar methods) cannot be resolved to a variable. Everything except this variable is accepted. Any idea why this is occurring? Note: My libs folder contains everything in here:
https://github.com/DushyanthMaguluru/ZBarScanner/tree/master/ZBarScannerLibrary/libs
and zbar.jar is included on the build path.
ScanActivity:
package com.xx.xxx;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.view.Menu;
import android.view.View;
import android.widget.Toast;
import com.dm.zbar.android.scanner.ZBarConstants;
import com.dm.zbar.android.scanner.ZBarScannerActivity;
import net.sourceforge.zbar.Symbol;
public class ScanActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scan);
}
public void launchScanner(View v) {
if (isCameraAvailable()) {
Intent intent = new Intent(this, ZBarScannerActivity.class);
startActivityForResult(intent, ZBAR_SCANNER_REQUEST);
} else {
Toast.makeText(this, "Rear Facing Camera Unavailable", Toast.LENGTH_SHORT).show();
}
}
public void launchQRScanner(View v) {
if (isCameraAvailable()) {
Intent intent = new Intent(this, ZBarScannerActivity.class);
intent.putExtra(ZBarConstants.SCAN_MODES, new int[]{Symbol.QRCODE});
startActivityForResult(intent, ZBAR_SCANNER_REQUEST);
} else {
Toast.makeText(this, "Rear Facing Camera Unavailable", Toast.LENGTH_SHORT).show();
}
}
public boolean isCameraAvailable() {
PackageManager pm = getPackageManager();
return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case ZBAR_SCANNER_REQUEST:
case ZBAR_QR_SCANNER_REQUEST:
if (resultCode == RESULT_OK) {
Toast.makeText(this, "Scan Result = " + data.getStringExtra(ZBarConstants.SCAN_RESULT), Toast.LENGTH_SHORT).show();
}
break;
}
}
}
Just in case it is relevant:
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.xx.xxx"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature
android:name="android.hardware.camera"
android:required="false" />
<application
android:icon="#drawable/ic_launcher"
android:label="xx"
android:theme="#style/AppTheme" >
<activity android:name="com.xx.xxx.MainActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.xx.xxx.WvActivity" />
<activity android:name="com.xx.xxx.ScanActivity" />
<activity
android:name="com.dm.zbar.android.scanner.ZBarScannerActivity"
android:screenOrientation="landscape" />
</application>

I checked the ZBar Library Example. You made a mistake.
This error occurred because you did not declare these two variables in your activity
private static final int ZBAR_SCANNER_REQUEST = 0;
private static final int ZBAR_QR_SCANNER_REQUEST = 1;
you need to declare these variables above your onCreate(..) Method.
See the ZBar Example.

Starting Activity from a non-Activity in c2dm not showing

I am trying to display messages from C2DM so When I start an Activity from a non activity it works but only first time. My activity contains View and close button so if the user is not inside the app when he receive the push notification then it should start the app when he press view button or close it on close this works as well but when user press view button and enters the app after than I am unable to start the activity again, it seems like the activity is there but its not visible to user. My code is as below , hope you understand what I am saying. The C2DM code example used is taken from here
C2DMReceiver
package com.mks.android.example;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import com.google.android.c2dm.C2DMBaseReceiver;
import com.google.android.c2dm.C2DMessaging;
import com.mks.android.example.activity.MessageDialogActivity;
public class C2DMReceiver extends C2DMBaseReceiver {
private static String senderId = "mysenderemail#gmail.com";
String registrationId;
public C2DMReceiver() {
super(senderId);
}
#Override
public void onRegistrered(Context context, String registrationId) {
this.registrationId = registrationId;
Log.e("Error", registrationId);
}
#Override
public void onUnregistered(Context context) {
C2DMessaging.register(context, senderId);
}
#Override
public void onError(Context context, String errorId) {
Log.w("Error", errorId);
}
#Override
protected void onMessage(Context context, Intent intent) {
Log.i("Error", "MessageReceived");
Bundle bundle = intent.getExtras();
intent = new Intent();
intent.putExtra("messageBundle", bundle);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
intent.setClass(context, MessageDialogActivity.class);
startActivity(intent);
// load message display activity here
}
}
MESSAGE DIALOG ACTIVITY CLASS
package com.mks.android.example.activity;
import android.app.Activity;
import android.content.ComponentName;
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;
import com.mks.android.example.R;
import com.mks.android.example.activity.list.Functions;
public class MessageDialogActivity extends Activity {
private Functions func = new Functions();
private int isAppActive = 0;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
showMessages();
}
private void showMessages(){
Bundle bundle = getIntent().getBundleExtra("messageBundle");
String title = bundle.getString("title");
String message = bundle.getString("message");
setContentView(R.layout.c2dm_message);
TextView txtTitle = (TextView) findViewById(R.id.title);
TextView txtMessage = (TextView) findViewById(R.id.message);
Button btnView = (Button) findViewById(R.id.btnView);
Button btnClose = (Button) findViewById(R.id.btnClose);
txtTitle.setText(title);
txtMessage.setText(message);
this.isAppActive = func.getAppState(this);
if(isAppActive==1){
btnView.setVisibility(View.GONE);
}
btnView.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if(isAppActive == 0){
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.setComponent(new ComponentName("com.mks.android.example","com.mks.android.example.activity.MainActivity"));
startActivity(intent);
}
MessageDialogActivity.this.finish();
}
});
btnClose.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
}
#Override
protected void onNewIntent(Intent intent) {
setIntent(intent);
showMessages();
}
}
AndroidManifest FIle
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mks.android.example"
android:versionCode="1"
android:versionName="1.0" android:installLocation="preferExternal">
<uses-sdk android:minSdkVersion="4" />
<application android:label="#string/app_name" android:icon="#drawable/icon_launcher" android:debuggable="true">
<uses-library android:name="com.google.android.maps" />
<activity android:name=".activity.MainActivity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:theme="#android:style/Theme.NoTitleBar" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".activity.MessageDialogActivity" android:theme="#style/DialogNoTitle" android:activity android:launchMode="singleTop" />
<service android:name=".C2DMReceiver" />
<!-- Only C2DM servers can send messages for the app. If permission is not set - any other app can generate it -->
<receiver android:name="com.google.android.c2dm.C2DMBroadcastReceiver" android:permission="com.google.android.c2dm.permission.SEND">
<!-- Receive the actual message -->
<intent-filter>
<action android:name="com.google.android.c2dm.intent.RECEIVE" />
<category android:name="com.mks.android.example" />
</intent-filter>
<!-- Receive the registration id -->
<intent-filter>
<action android:name="com.google.android.c2dm.intent.REGISTRATION" />
<category android:name="com.mks.android.example" />
</intent-filter>
</receiver>
</application>
<supports-screens android:smallScreens="true"
android:normalScreens="true"
android:largeScreens="true"
android:anyDensity="true" />
<permission android:name="com.mks.android.example.permission.C2D_MESSAGE" android:protectionLevel="signature" />
<uses-permission android:name="com.mks.android.example.permission.C2D_MESSAGE" />
<!-- This app has permission to register and receive message -->
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.INTERNET" />
</manifest>
If i remove androidLaunchMode singleTop form manifest file and add set flag to multipleTask in C2DMReciver class it works but i get lots of dialog for each message. Thanks for help .

Set flag to singletop , the code to call messagedialogactivity is as under:
Intent intent = new Intent();
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.setClass(context, MessageDialogActivity.class);