0，消息提示

1，Toast

2，Notification

• 0，消息提示

当程序有大量信息需向用户提示，可以考虑对话框

如果只是少量信息，可以考虑“更轻量级”的消息提示

• 1，消息提示

Toast是一个非常方便的提示消息框，

特点：①不会获得焦点    ②过一段时间会自动消失

使用步骤：

①调用Toast构造器或makeText()，创建一个Toast对象

②调用Toast的方法设置消息提示的对齐方式，边距和内容等

③调用Toast的show()

实例：

public class ToastActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				Toast.makeText(ToastActivity.this, "简单的Toast", Toast.LENGTH_SHORT).show();
			}
		});
        
        findViewById(R.id.button2).setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				Toast toast = Toast.makeText(ToastActivity.this, "带图片的Toast", Toast.LENGTH_LONG);
				toast.setGravity(Gravity.CENTER, 0, 0);
				
				View view = toast.getView();
				
				ImageView imageView = new ImageView(ToastActivity.this);
				imageView.setImageResource(R.drawable.ic_launcher);
				
				LinearLayout layout = new LinearLayout(ToastActivity.this);
				layout.addView(imageView);
				layout.addView(view);
				
				toast.setView(layout);
				toast.show();
				
			}
		});
    }
}

• 2，Notify

手机状态栏的通知

使用步骤：

①getSystemService(NOTIFICATION_SERVICE)获得NotificationManager服务

②通过构造器创建一个Notification对象

③为Notification设置各种参数

④通过NotificationManager发送Notification

public class NotificationActivity extends Activity {
	static final int My_ID = 1;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				Intent intent = new Intent(NotificationActivity.this, OtherActivity.class);
				PendingIntent pi = PendingIntent.getActivity(NotificationActivity.this, 0, intent, 0);
				
				Notification notification = new Notification();
				notification.icon = R.drawable.ic_launcher;
				notification.tickerText = "启动其他Activity的链接";
				notification.when = System.currentTimeMillis();
				notification.defaults = Notification.DEFAULT_ALL;
				notification.setLatestEventInfo(NotificationActivity.this,
						"通知",
						"点击进入OtherActivity",
						pi);
				
				NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
				nm.notify(My_ID, notification);
			}
		});
        
        findViewById(R.id.button2).setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
				nm.cancel(My_ID);
			}
		});
        
    }
}

 解析：

①PendingIntent对象封装了一个Intent，所以单击Notification会调整页面