Android简易实战教程--第二话《两种进度条》

Posted 2020-07-27 杨道龙

点击按钮模拟进度条下载进度，“下载”完成进度条消失。

代码如下：

xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<ProgressBar
	android:id="@+id/firstBar"
	style="?android:attr/progressBarStyleHorizontal"
	android:layout_width="200dp"
	android:layout_height="wrap_content"
	android:visibility="gone"
	/>
<ProgressBar
	android:id="@+id/secondBar"
	style="?android:attr/progressBarStyle"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:visibility="gone"
	/>
<Button
	android:id="@+id/myButton"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:text="begin"
	/>
</LinearLayout>

Activity：

package ydl.progressbar;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;

public class ProgressBarTest extends Activity {
    /** Called when the activity is first created. */
	//声明变量
	private ProgressBar firstBar =null;
	private ProgressBar secondBar = null;
	private Button myButton = null;
	private int i = 0 ;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //根据控件的ID来取得代表控件的对象
        firstBar = (ProgressBar)findViewById(R.id.firstBar);
        secondBar = (ProgressBar)findViewById(R.id.secondBar);
        myButton = (Button)findViewById(R.id.myButton);
        myButton.setOnClickListener(new ButtonListener());
    }
    class ButtonListener implements OnClickListener{
    	
		@Override
		public void onClick(View v) {
			if(i == 0)
			{
				//设置进度条处于可见的状态
				firstBar.setVisibility(View.VISIBLE);
				firstBar.setMax(150);//手动设置最大值，默认是100
				secondBar.setVisibility(View.VISIBLE);
			}
			else if ( i < firstBar.getMax()){
				//设置主进度条的当前值
				firstBar.setProgress(i);
				//设置第二进度条的当前值
				firstBar.setSecondaryProgress(i + 10);
				//因为默认的进度条无法显示进行的状态
				//secondBar.setProgress(i);
				
			}
			else{
				//设置进度条处于不可见状态
				firstBar.setVisibility(View.GONE);
				secondBar.setVisibility(View.GONE);
			}
			i = i + 10 ;
		}
    	
    }
    
}