Android Development - Snippets

Neue Activity starten

Z.B. über Button Klick

Du brauchst:

• Neue Activity
  • Evtl. neues Layout anlegen
  • Neue Java Klasse für Activity anlegen
  • Neue Activity im Manifest eintragen

• Button in der Haupt Activity
• onClick Event Handler
• Intent als Verbindung

• Ressourcen wie Strings etc.

Neues Layout für die Activity

Layout Ordner > Rechtsklick > New > Android Layout File > Name in Lowercase(z.b. page_2)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/page2_title"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

Neue Activity Klasse erzeugen

Package > Rechtsklick > New > Class > Name mit FirstLetterUppercase (z.B. Page2Activity)

• extends Activity
• Activity importieren
• mind. onCreate(bundle) -> am Besten über Rechtsklick > Source > Override
• setcontentView(R.layout.id)

page2Activity.class

package com.example.buttonstartsactivity;

import android.app.Activity;
import android.os.Bundle;

public class Page2Activity extends Activity{

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.page2);
	}
}

Manifest Eintrag

// ...
        <activity
            android:name="com.example.buttonstartsactivity.Page2Activity"
            android:label="@string/app_name" 
            android:exported="false">
            <intent-filter>
                <action android:name="android.intent.action.PAGE2" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
// ...

Button in Hauptansicht

z.B.

main_activtiy.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:text="@string/button" />

</RelativeLayout>