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。

第一个参数：当前的上下文环境。可用getApplicationContext()或者getContext()或this

第二个参数：要显示的字符串。也可是R.string中字符串ID

第三个参数：显示的时间长短。Toast默认的有两个LENGTH_LONG(长3.5秒)和LENGTH_SHORT(短2秒)，也可以使用毫秒如1000ms（不建议）

Toast 是一个 View 视图，快速的为用户显示少量的信息。 Toast 在应用程序上浮动显示信息给用户，不会获得焦点，不影响用户的输入或其他操作，主要用于 一些帮助或者提示。
Toast 最常见的创建方式是使用静态方法 Toast.makeText
下面用一个实例来看看如何使用Toast。
 

1.默认效果

代码

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

2.自定义显示位置效果

代码

toast = Toast.makeText(getApplicationContext(),
     "自定义位置Toast", Toast.LENGTH_LONG);
   toast.setGravity(Gravity.CENTER, 0, 0);
   toast.show();

3.带图片效果

代码

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();

4.完全自定义效果

代码

LayoutInflater inflater = getLayoutInflater();
   View layout = inflater.inflate(R.layout.custom,
     (ViewGroup) findViewById(R.id.llToast));
   ImageView image = (ImageView) layout
     .findViewById(R.id.tvImageToast);
   image.setImageResource(R.drawable.icon);
   TextView title = (TextView) layout.findViewById(R.id.tvTitleToast);
   title.setText("Attention");
   TextView text = (TextView) layout.findViewById(R.id.tvTextToast);
   text.setText("完全自定义Toast");
   toast = new Toast(getApplicationContext());
   toast.setGravity(Gravity.RIGHT | Gravity.TOP, 12, 40);
   toast.setDuration(Toast.LENGTH_LONG);
   toast.setView(layout);
   toast.show();

5.其他线程

 代码

new Thread(new Runnable() {
    public void run() {
     showToast();
    }
   }).start();

完整代码

1.Main,java

package com.wjq.toast;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

public class Main extends Activity implements OnClickListener {
 Handler handler = new Handler();

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  findViewById(R.id.btnSimpleToast).setOnClickListener(this);
  findViewById(R.id.btnSimpleToastWithCustomPosition).setOnClickListener(
    this);
  findViewById(R.id.btnSimpleToastWithImage).setOnClickListener(this);
  findViewById(R.id.btnCustomToast).setOnClickListener(this);
  findViewById(R.id.btnRunToastFromOtherThread).setOnClickListener(this);

 }

 public void showToast() {
  handler.post(new Runnable() {

   @Override
   public void run() {
    Toast.makeText(getApplicationContext(), "我来自其他线程！",
      Toast.LENGTH_SHORT).show();

   }
  });
 }

 @Override
 public void onClick(View v) {
  Toast toast = null;
  switch (v.getId()) {
  case R.id.btnSimpleToast:
   Toast.makeText(getApplicationContext(), "默认Toast样式",
     Toast.LENGTH_SHORT).show();
   break;
  case R.id.btnSimpleToastWithCustomPosition:
   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.btnSimpleToastWithImage:
   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.btnCustomToast:
   LayoutInflater inflater = getLayoutInflater();
   View layout = inflater.inflate(R.layout.custom,
     (ViewGroup) findViewById(R.id.llToast));
   ImageView image = (ImageView) layout
     .findViewById(R.id.tvImageToast);
   image.setImageResource(R.drawable.icon);
   TextView title = (TextView) layout.findViewById(R.id.tvTitleToast);
   title.setText("Attention");
   TextView text = (TextView) layout.findViewById(R.id.tvTextToast);
   text.setText("完全自定义Toast");
   toast = new Toast(getApplicationContext());
   toast.setGravity(Gravity.RIGHT | Gravity.TOP, 12, 40);
   toast.setDuration(Toast.LENGTH_LONG);
   toast.setView(layout);
   toast.show();
   break;
  case R.id.btnRunToastFromOtherThread:
   new Thread(new Runnable() {
    public void run() {
     showToast();
    }
   }).start();
   break;

  }

 }
}

2.main,xml

<?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" android:padding="5dip" android:gravity="center">
 <Button android:layout_height="wrap_content"
  android:layout_width="fill_parent" android:id="@+id/btnSimpleToast"
  android:text="默认"></Button>
 <Button android:layout_height="wrap_content"
  android:layout_width="fill_parent" android:text="自定义显示位置"
  android:id="@+id/btnSimpleToastWithCustomPosition"></Button>
 <Button android:layout_height="wrap_content"
  android:layout_width="fill_parent" android:id="@+id/btnSimpleToastWithImage"
  android:text="带图片"></Button>
 <Button android:layout_height="wrap_content"
  android:layout_width="fill_parent" android:text="完全自定义"
  android:id="@+id/btnCustomToast"></Button>
 <Button android:layout_height="wrap_content"
  android:layout_width="fill_parent" android:text="其他线程"
  android:id="@+id/btnRunToastFromOtherThread"></Button>

</LinearLayout>

3.custom.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_height="wrap_content" android:layout_width="wrap_content"
 android:background="#ffffffff" android:orientation="vertical"
 android:id="@+id/llToast" >
 <TextView
  android:layout_height="wrap_content"
  android:layout_margin="1dip"
  android:textColor="#ffffffff"
  android:layout_width="fill_parent"
  android:gravity="center"
  android:background="#bb000000"
  android:id="@+id/tvTitleToast" />
 <LinearLayout
  android:layout_height="wrap_content"
  android:orientation="vertical"
  android:id="@+id/llToastContent"
  android:layout_marginLeft="1dip"
  android:layout_marginRight="1dip"
  android:layout_marginBottom="1dip"
  android:layout_width="wrap_content"
  android:padding="15dip"
  android:background="#44000000" >
  <ImageView
   android:layout_height="wrap_content"
   android:layout_gravity="center"
   android:layout_width="wrap_content"
   android:id="@+id/tvImageToast" />
  <TextView
   android:layout_height="wrap_content"
   android:paddingRight="10dip"
   android:paddingLeft="10dip"
   android:layout_width="wrap_content"
   android:gravity="center"
   android:textColor="#ff000000"
   android:id="@+id/tvTextToast" />
 </LinearLayout>
</LinearLayout>