java - How to iterate through a HashMap

MainActivity.java

 package com.cfsuman.me.javaexamples;  import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.Window; import android.widget.RelativeLayout; import android.widget.TextView;  import java.util.HashMap; import java.util.Iterator; import java.util.Map;   public class MainActivity extends AppCompatActivity {     private String mTitle = "Java - How to iterate through a HashMap";      @Override     protected void onCreate(Bundle savedInstanceState) {         requestWindowFeature(Window.FEATURE_ACTION_BAR);         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          getSupportActionBar().setTitle(mTitle);         getSupportActionBar().setBackgroundDrawable(new ColorDrawable(Color.RED));          // Get widget reference from XML layout         RelativeLayout rl = (RelativeLayout) findViewById(R.id.rl);         TextView tv = (TextView) findViewById(R.id.tv);          // Empty the TextView         tv.setText("");          // Initializing a new HashMap         HashMap<String, String> colors = new HashMap<>();         // Put some key value pairs to HashMap         colors.put("Red", "#FF0000");         colors.put("Green", "#008000");         colors.put("Blue", "#0000FF");          // Iterate through the HashMap         Iterator itr = colors.entrySet().iterator();         tv.setText(tv.getText()+"Iterate over a HashMap");         while(itr.hasNext()){             Map.Entry pair = (Map.Entry) itr.next();             tv.setText(tv.getText() + "\n" + pair.getKey() + " : " + pair.getValue());             //iterator.remove();         }          // Another way to iterate through the HashMap         tv.setText(tv.getText()+"\n\nAnother way to iterate over a HashMap");         for(Map.Entry<String,String > entry : colors.entrySet()){             tv.setText(tv.getText() + "\n" + entry.getKey() + " : " + entry.getValue());         }          // Another way to iterate over HashMap keys and get values also         tv.setText(tv.getText()+"\n\nAnother way to iterate over a HashMap");         for(String key : colors.keySet()){             tv.setText(tv.getText() + "\n" + key + " : " + colors.get(key));         }          // Iterate over HashMap keys only         tv.setText(tv.getText()+"\n\nIterate over HashMap keys only");         for(String key : colors.keySet()){             tv.setText(tv.getText() + "\n" + key);         }          // Iterate over HashMap values only         tv.setText(tv.getText()+"\n\nIterate over HashMap values only");         for(String value : colors.values()){             tv.setText(tv.getText() + "\n" + value);         }     } } 

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