模拟文件拷贝

模拟文件拷贝:
要求：要用progressDialog和子线程来模拟显示拷贝进度；进度完成后在主界面提示拷贝完成，分别使用普通方式和消息机制编写。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.wang.xuexi.CopyActivity"
    android:orientation="vertical">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="拷贝"
        android:onClick="bt_OnClick"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="拷贝结果"
        android:id="@+id/tv_2"/>


</LinearLayout>

package com.example.wang.xuexi;

import android.app.ProgressDialog;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class CopyActivity extends AppCompatActivity {

    TextView tv_2;

    Handler h=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);

            if (msg.what==100)
            {
                String m=msg.obj.toString();

                tv_2.setText(m);
            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_copy);

        tv_2=(TextView)findViewById(R.id.tv_2);
    }

    public void bt_OnClick(View v)
    {
        final ProgressDialog progressDialog=new ProgressDialog(this);

        progressDialog.setTitle("正在拷贝");
        progressDialog.setMessage("请等待...");
        progressDialog.setCancelable(false);

        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

        progressDialog.show();

        new  Thread(new Runnable() {
            @Override
            public void run() {

                for (int i=0;i<=100;i++)
                {
                    progressDialog.setProgress(i);

                    try {

                        Thread.sleep(200);
                    }catch (Exception e){

                    }
                }


                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {

//                        tv_2.setText("拷贝完成");

                        Message m=Message.obtain();
                        m.what=100;
                        m.obj="拷贝完成";
                        h.sendMessage(m);

                    }
                });

                progressDialog.dismiss();

            }
        }).start();



    }
}