Handler嵌套--可以

package com.example.handlernestdemo;

import android.support.v7.app.ActionBarActivity;

import android.annotation.SuppressLint;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.view.View;

import android.widget.Button;

import android.widget.Toast;

@SuppressLint("HandlerLeak")

public class MainActivity extends ActionBarActivity {

    private Handler mHandler = new Handler() {

        @Override

        public void handleMessage(Message msg) {

            switch (msg.what) {

            case 1:

                Message msg1 = obtainMessage();

                msg1.what = 1;

                // myHandler再次发送

                myHandler.sendMessage(msg1);

                break;

            default:

                break;

            }

            super.handleMessage(msg);

        }

    };

    private Handler myHandler = new Handler() {

        @Override

        public void handleMessage(Message msg) {

            switch (msg.what) {

            case 1:

                Toast.makeText(getApplicationContext(), "嵌套实现了。", Toast.LENGTH_LONG).show();

                break;

            default:

                break;

            }

            super.handleMessage(msg);

        }

    };

    private Button button1;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        button1 = (Button) findViewById(R.id.button1);

        button1.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Message message = new Message();

                message.what = 1;

                // mHandler按钮发送一个message

                mHandler.sendMessage(message);

            }

        });

    }

}