android Handler控制进度条（ProgressBar）实例

本文通过一个小例子来学习Handler的使用--Handler来控制进度条（ProgressBar）的进度。

1.布局文件activity_main.xml

<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="cn.sehzh.handlertester.MainActivity" >

<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="16dp"
android:max="300" />

<Button
android:id="@+id/startButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/progressBar"
android:layout_centerHorizontal="true"
android:layout_marginTop="117dp"
android:text="Start" />

</RelativeLayout>
2.MainActivity
package cn.sehzh.handlertester;

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

public class MainActivity extends Activity {
private ProgressBar mProgressBar;
private Button mStartBtn;
private int mProgressBarStatus = 0;
private Handler mHandler;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

init();
}

private void init() {
findView();

mHandler = new Handler();
mStartBtn.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
mStartBtn.setClickable(false);
new Thread(new Runnable() {
public void run() {
try {
while (mProgressBarStatus < mProgressBar.getMax()) {
mProgressBarStatus += 5;
Thread.sleep(1000);
mHandler.post(new Runnable() {
public void run() {
mProgressBar.setProgress(mProgressBarStatus);
}
});
}

} catch (InterruptedException e) {
e.printStackTrace();
}
}
}).start();
}
});
}

private void findView() {
mProgressBar = (ProgressBar) findViewById(R.id.progressBar);
mStartBtn = (Button) findViewById(R.id.startButton);
}

}
3.实现效果