进度条ProgressBar

拖动滑块改变图片透明度

1.布局

<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:orientation="vertical"
    tools:context=".AndroidProgerssBarActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="任务完成进度" />

    <ProgressBar
        android:id="@+id/bar"
        style="@android:style/Widget.ProgressBar.Horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="100" />

    <ProgressBar
        android:id="@+id/bar2"
        style="@android:style/Widget.ProgressBar.Horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="100"
        android:progressDrawable="@drawable/ic_launcher" >
    </ProgressBar>

    <Button
        android:id="@+id/btn1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="显示进度条" />
     <Button
        android:id="@+id/btn2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="不显示进度条" />

</LinearLayout>

2.逻辑控制

package com.example.androidprogerssbar;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.Button;
import android.widget.ProgressBar;

public class AndroidProgerssBarActivity extends Activity {

    // 模拟填充长度为100的数组
    private int[] data = new int[100];
    int hasData = 0;
    // 记录ProgressBar完成进度
    int status = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //设置窗口特征，启用显示进度的进度条
        requestWindowFeature(Window.FEATURE_PROGRESS);
        //设置窗口特征，不启用显示进度的进度条
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        setContentView(R.layout.activity_android_progerss_bar);
        Button btn1=(Button)this.findViewById(R.id.btn1);
        Button btn2=(Button)this.findViewById(R.id.btn2);
        
        final ProgressBar bar = (ProgressBar) this.findViewById(R.id.bar);
        final ProgressBar bar2 = (ProgressBar) this.findViewById(R.id.bar2);

        btn1.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View arg0) {
                //显示不带进度的进度条
                setProgressBarIndeterminateVisibility(true);
                //显示带进度的进度条
                setProgressBarVisibility(true);
                //设置进度条进度
                setProgress(4500);
            }
        });
        
    btn2.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View arg0) {
                //显示不带进度的进度条
                setProgressBarIndeterminateVisibility(false);
                //显示带进度的进度条
                setProgressBarVisibility(false);
            }
        });
    
        // 创建一个负责更新进度的Handler
        final Handler handler = new Handler() {

            @Override
            public void handleMessage(Message msg) {
                // 表明消息是由该程序发送的
                if (msg.what == 0x111) {
                    bar.setProgress(status);
                    bar2.setProgress(status);
                }
            }

        };

        // 启动线程执行任务
        new Thread() {
            public void run() {
                while (status < 100) {
                    // 获得耗时操作的完成百分比
                    status = doWork();
                    // 发送消息到Handler
                    Message m = new Message();
                    m.what = 0x111;
                    // 发送消息
                    handler.sendMessage(m);
                }
            }
        }.start();
    }

    // 模拟一个耗时操作
    public int doWork() {
        data[hasData++] = (int) (Math.random() * 100);
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return hasData;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_android_progerss_bar, menu);
        return true;
    }

}