我们在做android开发的时候经常会遇到后台线程执行的比如说下载文件的时候,这个时候我们希望让客户能看到后台有操作进行，这时候我们就可以使用进度条,那么既然在后台运行,为的就是尽量不占用当前操作空间，用户可能还要进行其他操作,最好的方法就是在通知栏有个通知消息并且有个进度条。本文给一个例子工读者参考.
效果图如下：
主界面只有一个按钮就不上文件了
通知栏显示所用到的布局文件content_view.xml
我要评论
<?xml version="1.0" encoding="utf-8"?>
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#00000000"
android:orientation="vertical"
android:padding="5dp">
<imageview
android:id="@+id/content_view_image"
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@drawable/logo"
/>
<textview
android:id="@+id/content_view_text1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0%"
android:textcolor="#000000"
android:layout_torightof="@id/content_view_image"
android:layout_centerhorizontal="true"
android:layout_margintop="5dp"
android:layout_marginleft="15dp"
/>
<progressbar
android:id="@+id/content_view_progress"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
style="@android:style/widget.progressbar.horizontal"
android:max="100"
android:layout_below="@id/content_view_image"
android:layout_margintop="4dp"
/>
</relativelayout>
主运行类：
package yyy.testandroid4;
import java.util.timer;
import java.util.timertask;
import android.app.activity;
import android.app.alertdialog.builder;
import android.app.notification;
import android.app.notificationmanager;
import android.app.pendingintent;
import android.content.dialoginterface;
import android.content.intent;
import android.content.pm.packagemanager.namenotfoundexception;
import android.os.bundle;
import android.os.handler;
import android.os.message;
import android.view.view;
import android.view.view.onclicklistener;
import android.widget.button;
import android.widget.remoteviews;
import android.widget.toast;
public class testandroid4activity extends activity {
private handler handler = new handler(){
@override
public void handlemessage(message msg) {
// todo auto-generated method stub
super.handlemessage(msg);
switch (msg.what) {
case 0:
notif.contentview.settextviewtext(r.id.content_view_text1, len+"%");
notif.contentview.setprogressbar(r.id.content_view_progress, 100, len, false);
manager.notify(0, notif);
break;
case 1:
toast.maketext(testandroid4activity.this, "下载完成", 0).show();
break;
default:
break;
}
}
};
private button update,cancel;
private int localversion,serverversion;
private int len;
private notificationmanager manager;
private notification notif;
/** called when the activity is first created. */
@override
public void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.main);
update = (button) findviewbyid(r.id.update);
update.setonclicklistener(new onclicklistener() {
@override
public void onclick(view arg0) {
// todo auto-generated method stub
//点击通知栏后打开的activity
intent intent = new intent(testandroid4activity.this,otheractivity.class);
pendingintent pintent = pendingintent.getactivity(testandroid4activity.this, 0, intent, 0);
manager = (notificationmanager) getsystemservice(notification_service);
notif = new notification();
notif.icon = r.drawable.logo;
notif.tickertext = "新通知";
//通知栏显示所用到的布局文件
notif.contentview = new remoteviews(getpackagename(), r.layout.content_view);
notif.contentintent = pintent;
manager.notify(0, notif);
new downloadthread().start();
}
});
}
}
private class downloadthread extends thread{
private timer timer = new timer();
@override
public void run() {
// todo auto-generated method stub
super.run();
timer.schedule(new timertask() {
@override
public void run() {
// todo auto-generated method stub
message msg = new message();
msg.what = 0;
msg.obj = len;
handler.sendmessage(msg);
if(len == 100){
timer.cancel();
handler.sendemptymessage(1);
}
}
}, 0, 1000);
len = 0;
try {
while(len < 100){
len++;
thread.sleep(1000);
}
} catch (interruptedexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
}
}
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