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...

My app is Always crashing: Unable to instantiate activity

Help! when i run my app it will crash and give me that
java.lang.RuntimeException: Unable to instantiate activity
ComponentInfo{com.spinhaxo.consoleapp/com.spinhaxo.consoleapp.Console}:
java.lang.ClassNotFoundException: Didn't find class
"com.spinhaxo.consoleapp.Console" on path: /data/app/com.spinhaxo.consoleapp-1.apk
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2171)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2295)
at android.app.ActivityThread.access$700(ActivityThread.java:150)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1280)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:5279)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: Didn't find class
"com.spinhaxo.consoleapp.Console" on path: /data/app/com.spinhaxo.consoleapp-1.apk
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
at android.app.Instrumentation.newActivity(Instrumentation.java:1071)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
I dont know what to do :( on an Virtual device on my Pc its working fine, but on my mobile phone and Tablet its Crashing...
My Manifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.spinhaxo.consoleapp"
android:versionCode="5"
android:versionName="2.1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="11" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<application
android:icon="#drawable/icon"
android:label="#string/app_name" >
<activity
android:label="#string/app_name"
android:name=".Console"
>
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.startapp.android.publish.list3d.List3DActivity"
android:theme="#android:style/Theme" />
<activity android:name="com.startapp.android.publish.AppWallActivity"
android:theme="#android:style/Theme.Translucent"
android:configChanges="orientation|keyboardHidden|screenSize" />
<activity
android:icon="#drawable/frages"
android:label="BatteryInfo"
android:name=".BatteryInfo"
android:theme="#android:style/Theme.Dialog">
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
The onCreate of my MainActivity(Consolejar):
package com.spinhaxo.console;
import android.app.*;
import android.view.*;
import android.widget.TextView;
import android.content.DialogInterface;
import android.widget.Toast;
import android.view.Menu;
import android.net.wifi.*;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageInfo;
import android.os.BatteryManager;
import android.os.Bundle;
import android.os.Environment;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.view.View;
import android.widget.EditText;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import com.spinhaxo.consoleapp.R;
import com.startapp.android.publish.StartAppAd;
import com.startapp.android.publish.StartAppAd.AdMode;
import com.startapp.android.publish.StartAppSDK;
import com.startapp.android.publish.splash.SplashConfig;
import com.startapp.*;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.util.Log;
import com.google.analytics.tracking.android.EasyTracker;
import com.google.analytics.tracking.android.Fields;
import com.google.analytics.tracking.android.GoogleAnalytics;
import com.google.analytics.tracking.android.MapBuilder;
import com.google.analytics.tracking.android.Tracker;
public class Console extends Activity
{
private static Context context;
EditText console;
String folderPath;
File folder;
TextView output, stat_set, stat_devset, Zwischenablage_set;
private WifiManager wifiManager;
TextView invText, invtext2, invtext3, invtext4;
public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private ProgressDialog mProgressDialog;
String FILENAME = "Output.console";
String FILENAMEset = "Set_Autosave.set";
String FILENAMEdevset = "Set_DeveloperView.set";
String FileDownload = "Minecraft Pe.apk";
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
StartAppSDK.init(this, "108083436", "208381016", false);
setContentView(R.layout.main);
StartAppAd.showSplash(this, savedInstanceState,
new SplashConfig()
.setTheme(SplashConfig.Theme.OCEAN)
.setCustomScreen(R.layout.splash)
);
Zwischenablage_set = (TextView) findViewById(R.id.zwischenablage);
stat_set = (TextView) findViewById(R.id.stat_set);
stat_devset = (TextView) findViewById(R.id.stat_devset);
console = (EditText) findViewById(R.id.Console);
output = (TextView) findViewById(R.id.output);
invText = (TextView) findViewById(R.id.InvisibleText);
invtext2 = (TextView) findViewById(R.id.InvisibleText2);
invtext3 = (TextView) findViewById(R.id.InvisibleText3);
GoogleAnalytics.getInstance(this).getTracker("UA-53616112-1");
Tracker tracker = GoogleAnalytics.getInstance(this).getTracker("UA-53616112-1");
HashMap<String, String> hitParameters = new HashMap<String, String>();
hitParameters.put(Fields.HIT_TYPE, "appview");
hitParameters.put(Fields.SCREEN_NAME, "Home Screen");
tracker.send(hitParameters);
loaddevset(invtext3);
checkdevset();
createDir();
wifiManager = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);
this.registerReceiver(this.batteryInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
String read_data = null;
try {
File myFile = new File("/sdcard/Console/"+FILENAME);
FileInputStream fis = new FileInputStream(myFile);
byte[] dataArray = new byte[fis.available()];
while (fis.read(dataArray) != -1) {
read_data = new String(dataArray);
}
fis.close();
output.setText(read_data);
} catch (FileNotFoundException e) {
Toastmessage("Filenotfound");
e.printStackTrace();
} catch (IOException e) {
Toastmessage("IOException");
e.printStackTrace();
}
String vorheriges = output.getText().toString();
output.setText(vorheriges +"\n[System] Starting Console...\n[System] fetching data... \n[System] Console ready to work!");
loadset(invtext2);
I hope someone can help...

You are using different packages in your manifest and your Activity. Also you have multiple activities that are set as launchers, so remove
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
from the one that's not your main activity.
Here's an example manifest that should work:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.spinhaxo.console"
android:versionCode="5"
android:versionName="2.1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="11" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<application
android:icon="#drawable/icon"
android:label="#string/app_name" >
<activity
android:label="#string/app_name"
android:name=".Console">
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.startapp.android.publish.list3d.List3DActivity"
android:theme="#android:style/Theme" />
<activity android:name="com.startapp.android.publish.AppWallActivity"
android:theme="#android:style/Theme.Translucent"
android:configChanges="orientation|keyboardHidden|screenSize" />
<activity
android:icon="#drawable/frages"
android:label="BatteryInfo"
android:name=".BatteryInfo"
android:theme="#android:style/Theme.Dialog">
</activity>
</application>

Android vibrator app force close

my app force closes I do not know why. All it should do is vibrating when it is in the foreground and stop if it is not but when I start it on my phone it force closes. I added lines about vibrator usage into the manifest by hand. Maybe this is the problem. I have to anything else with it to be valid for the app?
My manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.kevinboonemidi"
android:versionCode="1"
android:versionName="1.0" >
<permission android:name="android.permission.VIBRATE" ></permission>
<uses-permission android:name="android.permission.VIBRATE"/>
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="8" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.haptic.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>
My code:
package com.example.haptic_sof;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import com.example.kevinboonemidi.R;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Vibrator;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
public class MainActivity extends Activity
{
protected Vibrator v = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
long pwmCycles[];
pwmCycles = new long[4];
v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
long[] pattern = { 0, 200, 10 };
v.vibrate(pattern, 0);
}
#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;
}
protected void onPause(){
super.onPause();
v.cancel();
}
protected void onStop()
{
super.onStop();
v.cancel();
}
}

Your packages are a mess.
You define com.example.kevinboonemidi as your package in the manifest, declare your Activity to be in com.example.haptic and actually put your Activity in com.example.haptic_sof.
Change android:name="com.example.haptic.MainActivity" to android:name="com.example.haptic_sof.MainActivity" and your app should run, though you may need to end up using one package entirely at least to start with.

Android Google Maps Fragment crashes

I have embedded Google Maps V2 in my App, as the Google Tutorial says.
I get the following errors, when switching to the map fragment.
03-08 12:52:01.600: E/AndroidRuntime(30314): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2105)
03-08 12:52:01.600: E/AndroidRuntime(30314): FATAL EXCEPTION: main
03-08 12:52:01.600: E/AndroidRuntime(30314): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{de.arvidg.exampleactionbartabs/de.arvidg.exampleactionbartabs.StartActivity}:
java.lang.ClassNotFoundException: de.arvidg.exampleactionbartabs.StartActivity
Heres the source code
package de.arvidg.exampleactionbartabs;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.maps.MapActivity;
import data.Device;
import data.Mission;
import de.arvidg.exampleactionbartabs.R;
import logic.FetchData;
import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
public class MapFrag extends MapFragment {
protected FetchData thread;
protected Device device;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View lView = inflater.inflate(R.layout.map, container,
false);
return lView;
}
public void setDumb() {
}
public Device getDevice() {
return device;
}
public void setDevice(Device device) {
this.device = device;
}
}
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.SupportMapFragment"/>
My Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="de.arvidg.exampleactionbartabs"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="14" />
<permission
android:name="de.arvidg.exampleactionbartabs.permission.MAPS_RECEIVE"
android:protectionLevel="signature" />
<uses-feature
android:glEsVersion="0x00020000"
android:required="true" />
<uses-permission android:name="de.arvidg.exampleactionbartabs.permission.MAPS_RECEIVE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name=".StartActivity"
android:label="#string/app_name"
android:theme="#android:style/Theme.Holo" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".MapFrag"
android:label="Map"
android:theme="#android:style/Theme.Holo" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="removed" />
<uses-library android:name="com.google.android.maps" />
</application>
</manifest>

change
android:name="com.google.android.gms.maps.MapFragment"/>
to
android:name="com.google.android.gms.maps.SupportMapFragment"/> in activity_main.xml
and change
public class MainActivity extends Activity
to
public class MainActivity extends FragmentActivity in MainActivity.java
these two fixes worked for me.

Android SecurityException ACCESS_WIFI_STATE

I am building an Android app that uses wifi.
I have properly declared these uses permissions in the manifest, however for some reason the app is throwing a SecurityException that causes the app to force-close.
I traced the cause of the security exception in LogCat to the system saying it doesn't have the access_wifi_state permission. This is strange and confusing to me because I have already declared it in the manifest.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="android.wifi"
android:versionCode="1"
android:versionName="1.0" >
<uses-permission android:name="ACCESS_WIFI_STATE" />
<uses-permission android:name="CHANGE_WIFI_STATE" />
<uses-feature android:name="android.hardware.wifi" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name="android.wifi.AndroidWiFiActivity"
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>
And here is the code that causes the exception:
package android.wifi;
import android.app.Activity;
import android.content.Context;
import android.net.wifi.WifiManager;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Button;
import android.widget.TextView;
import android.wifi.R;
public class AndroidWiFiActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView tv = (TextView) findViewById(R.id.textbox);
tv.setText("ABC 123");
WifiManager wifiMgr = (WifiManager) getSystemService(Context.WIFI_SERVICE);
if(wifiMgr.isWifiEnabled())
{
tv.append("Wifi is enabled");
}
else
{
tv.append("Wifi is disabled");
}
}
}
Any help is greatly appreciated. Thanks.

The permission is:
android.permission.ACCESS_WIFI_STATE