本文章主要介绍了Android控件之ProgressBar探究,具有不错的的参考价值,希望对您有所帮助,如解说有误或未考虑完全的地方,请您留言指出,谢谢!
ProgressBar位于android.widget包下,其继承于View,主要用于显示一些操作的进度。应用程序可以修改其长度表示当前后台操作的完成情况。因为进度条会移动,所以长时间加载某些资源或者执行某些耗时的操作时,不会使用户界面失去响应。ProgressBar类的使用非常简单,只需将其显示到前台,然后启动一个后台线程定时更改表示进度的数值即可。
以下ProgressBar跟Handle结合,模拟进度条的使用,当进度条完成时会跳转到TestActivity
main.xml布局文件
<? 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 " >
<!-- 长方形进度条,一开始不可见,直到点击按钮时才出现进度条 -->
< ProgressBar android:id = " @+id/progressBar "
style = " ?android:attr/progressBarStyleHorizontal "
mce_style = " ?android:attr/progressBarStyleHorizontal "
android:layout_width = " fill_parent "
android:layout_height = " wrap_content "
android:visibility = " gone "
android:max = " 100 " />
<!-- 圆形进度条 -->
<!--< ProgressBar android:id = " @+id/progressBar "
style = " ?android:attr/progressBarStyleLarge "
mce_style = " ?android:attr/progressBarStyleLarge "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content " />-->
< Button android:id = " @+id/start "
android:text = " 启动进度条 "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content " />
< Button android:id = " @+id/stop "
android:text = " 停止进度条 "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content " />
</ LinearLayout >
PbActivity类
package com.ljq.pb;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
public class PbActivity extends Activity {
private ProgressBar progressBar = null ;
private Button start = null , stop = null ;
// 定义Handler对象
private Handler handler = new Handler();
@Override
public void onCreate(Bundle savedInstanceState) {
super .onCreate(savedInstanceState);
setContentView(R.layout.main);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
progressBar.setProgress( 0 );
start = (Button) findViewById(R.id.start);
start.setOnClickListener( new View.OnClickListener() {
public void onClick(View v) {
handler.post(runnable); // 开始执行
}
});
stop = (Button)findViewById(R.id.stop);
stop.setOnClickListener( new View.OnClickListener() {
public void onClick(View v) {
handler.removeCallbacks(runnable); // 停止执行
progressBar.setProgress( 0 );
}
});
}
int pro = 0 ;
Runnable runnable = new Runnable(){
public void run() {
progressBar.setVisibility(View.VISIBLE);
pro = progressBar.getProgress() + 10 ;
progressBar.setProgress(pro);
// 如果进度小于100,,则延迟1000毫秒后重复执行runnable
if (pro < 100 ){
handler.postDelayed(runnable, 1000 );
} else {
progressBar.setVisibility(View.GONE);
startActivity( new Intent(PbActivity. this , TestActivity. class ));
handler.removeCallbacks(runnable);
progressBar.setProgress( 0 );
}
}
};
}
运行结果
原创文章,作者:奋斗,如若转载,请注明出处:https://blog.ytso.com/228174.html