XML : Android Studio Basic's First Excercise

I have been using Android Studio to create my first app. I am not using another IDE, Having gone thought the exercise I have reached errors in the following areas.

• My Activity
• Display Message Activity
• Gradle

DisplayMessageActivity

  `package com.company.myfirstapp;      import android.annotation.TargetApi;  import android.os.Build;    import static android.os.Build.*;    /**  * Created by MyActivity on 17/10/2015.  */    @Override  public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  // Get the message from the intent  Intent intent = getIntent();  String message = intent.getStringExtra(MyActivity.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);  }`    

MyActivity

  `package com.company.myfirstapp;     import android.content.Intent;   import android.support.v7.app.ActionBarActivity;   import android.os.Bundle;   import android.support.v7.app.AppCompatActivity;   import android.view.Menu;   import android.view.MenuItem;   import android.view.View;   import android.widget.EditText;     import com.company.myfirstapp.DisplayMessageActivity;   import com.company.myfirstapp.R;     public class MyActivity extends AppCompatActivity {    final public static String EXTRA_MESSAGE =                                                                                                                                                                                                                                                                                                            "com.company.myfirstapp.MESSAGE";    @Override  protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.activity_my);  }    @Override  public boolean onCreateOptionsMenu(Menu menu) {      // Inflate the menu; this adds items to the action bar if it is present.      getMenuInflater().inflate(R.menu.menu_my, menu);      return true;  }    @Override  public boolean onOptionsItemSelected(MenuItem item) {      // Handle action bar item clicks here. The action bar will      // automatically handle clicks on the Home/Up button, so long      // as you specify a parent activity in AndroidManifest.xml.      int id = item.getItemId();        //noinspection SimplifiableIfStatement      if (id == R.id.action_settings) {          return true;      }        return super.onOptionsItemSelected(item);  }        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);      MyActivity.this.startActivity(intent);      }  }    

}`

Ap

  apply plugin: 'com.android.application'    final def extension = android {  compileSdkVersion 22  buildToolsVersion "22.0.1"    defaultConfig {      applicationId "com.company.myfirstapp"      minSdkVersion 8      targetSdkVersion 22      versionCode 1      versionName "1.0"  }  buildTypes {      release {          minifyEnabled true          proguardFiles getDefaultProguardFile('proguard-android.txt'),     'proguard-rules.pro'      }   }  }  final def extension1 = extension  extension1    dependencies {  compile fileTree(dir: 'libs', include: ['*.jar'])  compile 'com.android.support:appcompat-v7:22.2.1'  }    

My First App

  // Top-level build file where you can add configuration options common to                 `all sub-projects/modules.    buildscript {  repositories {      jcenter()  }  dependencies {      classpath 'com.android.tools.build:gradle:1.2.3'        // NOTE: Do not place your application dependencies here; they belong      // in the individual module build.gradle files   }  }    allprojects {  repositories {      jcenter()  }    

}`

I have errors on Override and public void in Display Message Activity and Display Message in My Activity.