First time app developer and I'm trying to follow the lovely tutorial provided by the nice guys at Google.
Everything was going well until I got to the section on adding an ActionBar.
I tried following the instruction for supporting Android 2.1 and above. I went to the SDK manager, installed v7 appcompat, set up a new library project, imported appcompat, imported appcompat, set up the build paths, configured build paths, yadda yadda. Basically I followed these steps to the letter: http://developer.android.com/tools/support-library/setup.html#libs-with-res
Once that was done I adjusted MainActivity to extend ActionBarActivity and updated my manifest file to use Theme.AppCompat.Light for the theme. Continuing with the tutorial I added an ActionBar with a search and settings button, but upon trying to compile I ran into nothing but errors. Originally my rampant ctrl+shift+O'ing had imported android.R - a problem I found an fixed. However after removing that import statement and going to Project > Clean it isn't generating the R.java file. I've looked through every resource and there are no files with a capital letter in the name. There's also no errors in my XML files, and every reference to @string/<name> exists in the strings.xml file
Any advice on what to try next would be appreciated. I can also post the contents of any file that you suspect may be the culprit. I've spent around 4 hours trying to debug this myself but I don't know where to go next.
For @bluebrain:
Description Resource Location Type
Unable to resolve target 'android-16' android-support-v7-appcompat Uknown Android Target Problem
For @Gem_Ram:
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myfirstapp"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat.Light" >
<activity
android:name="com.example.myfirstapp.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="com.example.myfirstapp.DisplayMessageActivity"
android:label="@string/title_activity_display_message"
android:parentActivityName="com.example.myfirstapp.MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.myfirstapp.MainActivity" />
</activity>
</application>
</manifest>
MainActivity.java (Every occurrence of R is giving me "R cannot be resolved to a variable"):
package com.example.myfirstapp;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends ActionBarActivity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu items for use in the action bar
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.action_search:
//openSearch();
return true;
case R.id.action_settings:
//openSettings();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/** Called when the user clicks the Send button */
public void sendMessage(View view) {
// Do something in response to button
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
DisplayMessageActivity.java (same error):
package com.example.myfirstapp;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.NavUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class DisplayMessageActivity extends Activity {
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_message);
setupActionBar();
// Get the message from the intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);
}
/**
* Set up the {@link android.app.ActionBar}, if the API is available.
*/
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
private void setupActionBar() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
getActionBar().setDisplayHomeAsUpEnabled(true);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.display_message, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. Use NavUtils to allow users
// to navigate up one level in the application structure. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}
Strings.xml:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">My First App</string>
<string name="action_search">Search</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="edit_message">Enter a message</string>
<string name="button_send">Send</string>
<string name="title_activity_display_message">My Message</string>
</resources>
Any other files you'd like to see?
Update:
After changing import android.support.v7.app.ActionBarActivity; to import android.support.v7.app.ActionBar; I got a huge collection of red squigglies that I could not resolve since all of the methods I implemented and called are derivatives of the Activity class. I changed it back to import android.support.v7.app.ActionBarActivity; and hit save, then my Problems tab went berserk. First there were 63 problems, then 1, then 7, then 3, then 18... Problems ranging from some process failing with a negative return code, to variables being undefined, to some dependency not existing,... In an attempt to make Eclipse stop having a seizure I clicked Project > Clean, and now the old problem ("Unable to resolve target 'android-16'") is gone, and replaced by 7 instances of the problem "R cannot be resolved to a variable"
Of course this is the problem I expected all along, since my R.java file isn't being generated.
I has the same issue as you mentioned here. I imported library adroid-support-v7-appcompat and error say:
Unable to resolve target 'android-16' android-support-v7-appcompat Uknown Android Target Problem
then I opened project.properties file in android-support-v7-appcompat project and edit line
target=android-19
to
target=android-16
I saved change and make change back to
target=android-19
I saved everything and project was recompiled and all errors disappeared. Now Im able to run project and everything look fine.