Android控件开发之Toast

Toast是Android中用来显示显示信息的一种机制，和Dialog不一样的是，Toast是没有焦点的，而且Toast显示的时间有限，过一定的时间就会自动消失。

效果图





本程序main.xml源码

[html] view
plaincopy

<?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/btn1"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/btn1"/>

<Button

android:id="@+id/btn2"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/btn2" />

<Button

android:id="@+id/btn3"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/btn3"/>

<Button

android:id="@+id/btn4"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/btn4"/>

<Button

android:id="@+id/btn5"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/btn5" />

</LinearLayout>

[html] view
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java源码

package com.sx.Toast;

import android.app.Activity;

import android.os.Bundle;

import android.view.Gravity;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.LinearLayout;

import android.widget.Toast;

public class ToastActivity extends Activity

{

/** Called when the activity is first created. */

private Button btn1 = null;

private Button btn2 = null;

private Button btn3 = null;

private Button btn4 = null;

private Button btn5 = null;

@Override

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

//获取button对象通过ID

btn1 = (Button)findViewById(R.id.btn1);

btn2 = (Button)findViewById(R.id.btn2);

btn3 = (Button)findViewById(R.id.btn3);

btn4 = (Button)findViewById(R.id.btn4);

btn5 = (Button)findViewById(R.id.btn5);

//设置button监听器

btn1.setOnClickListener(new ButtonOnClicked());

btn2.setOnClickListener(new ButtonOnClicked());

btn3.setOnClickListener(new ButtonOnClicked());

btn4.setOnClickListener(new ButtonOnClicked());

btn5.setOnClickListener(new ButtonOnClicked());

}

class ButtonOnClicked implements OnClickListener

{

//注:getApplicationContext() 方法是程序当前的默认Context

@Override

public void onClick(View v)

{

// TODO Auto-generated method stub

Toast toast;

switch(v.getId())

{

case R.id.btn1:

Toast.makeText(getApplicationContext(), "默认Toast样式", Toast.LENGTH_LONG).show();

break;

case R.id.btn2:

toast = Toast.makeText(getApplicationContext(),"自定义位置Toast", Toast.LENGTH_LONG);

toast.setGravity(Gravity.CENTER, 0, 0);

toast.show();

break;

case R.id.btn3:

toast = Toast.makeText(getApplicationContext(), "带图片的Toast", Toast.LENGTH_LONG);

toast.setGravity(Gravity.CENTER, 0, 0);

LinearLayout toastView = (LinearLayout)toast.getView();

ImageView imageCodeProject = new ImageView(getApplicationContext());

imageCodeProject.setImageResource(R.drawable.icon);

toastView.addView(imageCodeProject, 0);

toast.show();

break;

case R.id.btn4:

break;

case R.id.btn5:

break;

}

}

}

}