AlertDialog setButton Deprecated

LayoutLib is too recent. Update your tool!
Eclipse Android Graphical layout resolving problem.

1. Open in Eclipse menu Help ->Check for Updates


2. Select updates: [caption id="attachment_593" width="300" caption="Android Eclipse updates dialog"][/caption]
   



3. Press Next and update all



4. Restart Eclipse


[caption id="attachment_596" align="alignleft" width="300" caption="Restart Eclipse if updates finished."][/caption]

Get key by value from Map Java Android example


MainClass.java

import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;

public class MainClass {
	public static void main(String[] arg) {

		// english;germany dictionary
		String[] arrayOfString = { "one;eine", "two;zwei", "two sets of;zwei"
				, "three;drei", "four;vier" };

		Map<String, String> map = new TreeMap<String, String>();

		for (String s : arrayOfString) {
			String[] array = s.split(";");
			String sKey = "", sValue = "";
			if (array.length > 1) {
				sKey = array[0];
				sValue = array[1];
				map.put(sKey, sValue);
			}
		}

		if (map.containsValue("zwei")) {
			Set<String> references = getKeysByValue(map, "zwei");
			 Iterator<String> it = references.iterator();
			    while (it.hasNext()) {
			      String key = (String) it.next();
			      String value = map.get(key);
			      System.out.println(key + " = " + value);
			    }
		}

	}

	public static <T, E> Set<T> getKeysByValue(Map<T, E> map, E value) {
		Set<T> keys = new HashSet<T>();
		for (Entry<T, E> entry : map.entrySet()) {
			if (entry.getValue().equals(value)) {
				keys.add(entry.getKey());
			}
		}
		return keys;
	}
}
/*
two = zwei
two sets of = zwei
 */

How add pair of strings to Hashtable, how get pair key value from Hashtable, how split string, basic Java Android example.

MainClass.java

import java.util.Enumeration;
import java.util.Hashtable;
public class MainClass {
	public static void main(String[] arg) {
		
		// english;germany dictionary
		String[] arrayOfString = { "one;eine", "two;zwei", "three;drei" };

	    Hashtable<String, String> hashTable = new Hashtable<String, String>();
	    for(String s: arrayOfString){
	    	String[] array = s.split(";");
	    	String sKey ="", sValue="";
	    	if(array.length > 1){
	    	sKey = array[0]; sValue = array[1];
	    		hashTable.put(sKey, sValue);
	    	}
	    }

	    Enumeration<String> enumer = hashTable.keys();
	    while (enumer.hasMoreElements()) {
	      String keyFromTable = (String) enumer.nextElement();
	      // get Returns the value to which the specified key is mapped, 
	      // or null if this map contains no mapping for the key
	      System.out.println(keyFromTable + " = " + hashTable.get(keyFromTable));
	    }       

	    
	}
}
/*
two = zwei
one = eine
three = drei
 */

1. File->Project Structure Ctrl + Alt + Shift + S



2. Select module and Dependencies Tab



3. Click on + PLUS button (right upper corner)



4. Select library


Click OK, OK

Log.e println needs a message error.
E/AndroidRuntime(330): FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{b.paint/b.paint.MainActivity}: java.lang.NullPointerException: println needs a message

Try this code:

		// Error
                String s = null;
		Log.e("bla", s); // !!! error Log.e println needs a message error.
                // OK
		String s = null;
		Log.e("bla", s+""); // OK