Handler的基本使用（1）之更新progressBar

实现：点击按钮，progressBar会自动地进行增操作。

效果：


点击后上面的progressbar会自动增加

布局文件：

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<ProgressBar
android:id="@+id/progressbar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:max="100"
style="?android:attr/progressBarStyleHorizontal"
android:visibility="gone"/>

<Button
android:id="@+id/button"
android:layout_below="@id/progressbar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="start!"/>

</RelativeLayout>

设置两个控件（进度条，按钮），

设置进度条为不可见状态，android:visibility="gone"，水平格式：style="?android:attr/progressBarStyleHorizontal"

src：

package com.shanl.handlerprogress;

import java.util.logging.LogRecord;

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

public class MainActivity extends Activity {

private ProgressBar bar;
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

bar = (ProgressBar)findViewById(R.id.progressbar);
button = (Button)findViewById(R.id.button);
buttonListener listener = new buttonListener();
button.setOnClickListener(listener);
}

class buttonListener implements OnClickListener{

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
System.out.println("The button is clicked");
bar.setVisibility(View.VISIBLE);//设置进度条可见状态
handler.post(thread);//调用线程
}
}

Handler handler = new Handler(){//复写handleMaessge函数，对消息进行处理
public void handleMessage(android.os.Message msg) {
bar.setProgress(msg.arg1);//设置进度条
handler.post(thread);//推进线程
};
};

Runnable thread = new Runnable() {
int i = 0;
@Override
public void run() {
// TODO Auto-generated method stub
i = i + 10;
Message msg = handler.obtainMessage();//获取消息对象
msg.arg1 = i;
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
// TODO: handle exception
System.out.println("InterruptedException");
}
handler.sendMessage(msg);//发送消息
if(i== 100){
handler.removeCallbacks(thread);//销毁线程
}
}
};

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

}

消息的处理如下所示：



这边的sendMessage，另一边handleMessage