Android UI How to - Raise alert or toast from Button click event








The following code shows how to Raise alert or toast from Button click event.

Example

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" >
  <Button
    android:id="@+id/alert"
    android:text="Raise an alert"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
  <Button
    android:id="@+id/toast"
    android:text="Make a toast"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
</LinearLayout>

Java code

/***/*  ww  w .  ja v a2  s  .  c o  m*/
  Copyright (c) 2008-2009 CommonsWare, LLC
  
  Licensed under the Apache License, Version 2.0 (the "License"); you may
  not use this file except in compliance with the License. You may obtain
  a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity implements View.OnClickListener {
  Button alert;
  Button toast;

  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    
    setContentView(R.layout.main);
    
    alert=(Button)findViewById(R.id.alert);
    alert.setOnClickListener(this);
    toast=(Button)findViewById(R.id.toast);
    toast.setOnClickListener(this);
  }
  
  public void onClick(View view) {
    if (view==alert) {
      new AlertDialog.Builder(this)
        .setTitle("MessageDemo")
        .setMessage("eek!")
        .setNeutralButton("Close", new DialogInterface.OnClickListener() {
          public void onClick(DialogInterface dlg, int sumthin) {
            // do nothing -- it will close on its own
          }
        })
        .show();
    }
    else {
      Toast
        .makeText(this, "<clink, clink>", Toast.LENGTH_SHORT)
        .show();
    }
  }
}
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