Making your app notice when a button was clicked is pretty simple, the code am giving you here is what I found to be the shortest method to do so.
The Result
We will make a button that updates a label with the current date when you click it. Pictures below.
Now when you the click button:
The Button Click Class (HelloAndroid.java)
package com.example.helloandroid; import java.util.Date; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.TextView; public class HelloAndroid extends Activity{ TextView date; @Override public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main); date=(TextView)findViewById(R.id.dateText); } public void showNewDate(View v) { date.setText(new Date().toString()); } }
The Android Manifest(AndroidManifest.xml)
Don’t forget to change android:minSdkVersion to the version you are using.
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.helloandroid" android:versionCode="1" android:versionName="1.0"> <uses-sdk android:minSdkVersion="13" /> <application android:icon="@drawable/icon" android:label="@string/app_name" android:debuggable="true"> <activity android:name=".HelloAndroid" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
The Layout(main.xml)
The line android:onClick is saving us from typing many more JAVA code lines. The value is the method in the JAVA file we want to execute when a user clicks the button.
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:text="You haven't clicked" android:id="@+id/dateText" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <Button android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Click Me" android:onClick="showNewDate"/> </LinearLayout>