ProgressBar（进度条）的使用和方法

image.png
image.png

activity:

package com.example.myapplication;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ProgressBar;

import java.lang.ref.WeakReference;

public class MainActivity extends AppCompatActivity {
    //该程序为模拟填充长度为100的数组
   private int[] data =new int[100];
   private int hasData=0;
   //记录progressBar的完成进度
    int status =0;
    private ProgressBar bar;
    private ProgressBar bar2;
    static class MyHander extends Handler
    {
        private WeakReference<MainActivity>activity;
        MyHander(WeakReference<MainActivity>activity){
            this.activity=activity;
        }

        @Override
        public void handleMessage(Message msg) {
            //表明消息是由该程序发送的
            if (msg.what==0x111)
            {
                activity.get().bar.setProgress(activity.get().status);
                activity.get().bar2.setProgress(activity.get().status);
            }
        }
    }
    //创建一个负责更新的进度条Handler
    MyHander myHander=new MyHander(new WeakReference<>(this));
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bar=findViewById(R.id.bar);
        bar2=findViewById(R.id.bar2);
        //启动线程来执行任务
        new Thread()
        {
            @Override
            public void run() {
                while (status<100)
                {
                    //获取操作的完成百分比
                    status=doWork();
                    //发送消息
                    myHander.sendEmptyMessage(0x11);
                }
            }
        }.start();
    }
    //模拟一个耗时操作
    public int doWork()
    {
        //为数组元素赋值
        data[hasData++]=(int)(Math.random() * 100);
        try {
            Thread.sleep(100);
        }catch (InterruptedException e)
        {
            e.printStackTrace();
        }
        return  hasData;
    }
}

my_bar.xml:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    //定义轨道背景
    <item android:id="@+id/no"
        android:drawable="@color/colorPrimaryDark"/>
    <item android:id="@+id/ok"
        android:drawable="@drawable/ic_launcher_foreground"/>
    </layer-list>

main_activity.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

  <LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="horizontal">
      //定义一个大环形的进度条
      <ProgressBar
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          style="@android:style/Widget.ProgressBar.Large" />
      //定义一个中等大小的进度条
      <ProgressBar
          android:layout_width="wrap_content"
          android:layout_height="wrap_content" />
      //定义一个小环进度条
      <ProgressBar
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          style="@android:style/Widget.ProgressBar.Small"/>
  </LinearLayout>
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="任务完成的进度"/>
    //定义一个水平进度条
    <ProgressBar
        android:id="@+id/bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="100"
        style="@android:style/Widget.ProgressBar.Horizontal"/>
    //定义一个水平进度条改变外观
    <ProgressBar
        android:id="@+id/bar2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="100"
        android:progressDrawable="@drawable/my_bar"
        style="@android:style/Widget.ProgressBar.Horizontal"/>
</LinearLayout>

效果图：

2.gif