android开发步步为营之2：开发自定义进度条对话框

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public class ProgressDialog extends AlertDialog

java.lang.Object

↳ android.app.Dialog

↳ android.app.AlertDialog

↳ android.app.ProgressDialog

从类的继承关系我们可以看到ProgressDialog继承至AlertDialog，所以我们今天自己写一个继承至AlertDialog的自定义进度条对话框。完成的功能是：下载盛付通的sdk，下载的过程中显示进度条，下载完毕之后将apk安装用户手机。开始我们的实验。

第一步、设计界面

主界面custompdview.xml 放置了一个按钮，用来触发下载apk事件

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout

xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

</RelativeLayout>

自定义ProgressDialog界面downloadprogressdialog.xml

放置了一个SeekBar其实和ProgressBar功能一样，就是长得不一样，两个TextView

SeekBar用来显示下载进度，其中一个TextView用来显示当前下载的总量，另外一个用来显示下载的百分比。

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_gravity="center_vertical" android:layout_width="fill_parent"

android:layout_height="wrap_content">

</RelativeLayout>

第二步、设计下载进度对话框DownloadProgressDialog.java

/**

package com.figo.helloworld;

import java.text.DecimalFormat;

import java.text.NumberFormat;

import android.app.AlertDialog;

import android.content.Context;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.view.LayoutInflater;

import android.view.View;

import android.widget.SeekBar;

import android.widget.TextView;

/**

* 自定义下载文件进度条对话框

* @author zhuzhifei

public class DownloadProgressDialog extends AlertDialog {

private SeekBar mProgress;//显示进度

private TextView mProgressNum;//显示下载总量

private TextView mProgressPercent;//显示下载百分比

public static final int M = 1024 * 1024;//M

public static final int K = 1024;//K

private double dMax;//文件大小

private double dProgress;//进度

private int middle = K;//默认为K

private int prev = 0;//开始值

private Handler mViewUpdateHandler;//Handler用来通知更新进度

private static final NumberFormat nf = NumberFormat.getPercentInstance();//进度格式

private static final DecimalFormat df = new DecimalFormat("###.##");//文件大小格式

public DownloadProgressDialog(Context context) {

super(context);

}

@Override

protected void onCreate(Bundle savedInstanceState) {

LayoutInflater inflater = LayoutInflater.from(getContext());

mViewUpdateHandler = new Handler() {

@Override

public void handleMessage(Message msg) {

//通过handler更新进度

super.handleMessage(msg);

double percent = dProgress / dMax;

if (prev != (int) (percent * 100)) {

mProgress.setProgress((int) (percent * 100));

mProgressNum.setText(df.format(dProgress) + "/"

+ df.format(dMax) + (middle == K ? "K" : "M"));

mProgressPercent.setText(nf.format(percent));

prev = (int) (percent * 100);

}

if (mProgress.getProgress() == 100) {

mProgressPercent.setText(nf.format(1));

}

};

//从自定义的对话框downloadprogressdialog.xml加载页面

View view = inflater.inflate(R.layout.downloadprogressdialog, null);

mProgress = (SeekBar) view.findViewById(R.id.seekbar);

mProgressNum = (TextView) view.findViewById(R.id.tvprogressnum);

mProgressPercent = (TextView) view.findViewById(R.id.tvprogresspercent);

setView(view);

onProgressChanged();

super.onCreate(savedInstanceState);

}

private void onProgressChanged() {

mViewUpdateHandler.sendEmptyMessage(0);//发送一条消息触发handleMessage事件

}

//获取下载文件的最大值

public double getDMax() {

return dMax;

}

//设置下载文件的最大值

public void setDMax(double max) {

if (max > M) {

middle = M;

} else {

middle = K;

}

dMax = max / middle;

}

//获取当前进度

public double getDProgress() {

return dProgress;

}

//设置当前进度

public void setDProgress(double progress) {

dProgress = progress / middle;

onProgressChanged();

}

第三步、设计Activity CustomPdActivity.java

/**

package com.figo.helloworld;

import java.io.File;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.net.URL;

import android.app.Activity;

import android.content.Context;

import android.content.Intent;

import android.net.Uri;

import android.os.AsyncTask;

import android.os.Bundle;

import android.os.Handler;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.Toast;

/**

* @author zhuzhifei

public class CustomPdActivity extends Activity implements OnClickListener {

protected Context context;//上下文

private DownloadProgressDialog progressDialog;//自定义进度对话框

private Button btncustom;//按钮

//加载主界面

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.custompdview);

btncustom = (Button) findViewById(R.id.btncustom);

btncustom.setOnClickListener(this);

context = getApplicationContext();

btncustom.setOnClickListener(this);

}

// 写一个下载异步任务

class DownLoadTask extends AsyncTask<Void, Integer, Uri> {

// 执行任务

@Override

protected Uri doInBackground(Void... params) {

return downLoad();

}

// 更新进度

@Override

protected void onProgressUpdate(Integer... progress) {

progressDialog.setDProgress(progress[0]);

}

// 任务执行完成之后

@Override

protected void onPostExecute(Uri result) {

if (progressDialog != null) {

progressDialog.dismiss();

}

if (result == null) {

Toast.makeText(context, "下载失败，请点击更新按钮重新下载", Toast.LENGTH_SHORT)

.show();

return;

}

Toast.makeText(context, "下载完毕,开始安装...", Toast.LENGTH_SHORT).show();

Intent intent = new Intent(Intent.ACTION_VIEW);

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

intent.setDataAndType(result,

"application/vnd.android.package-archive");

startActivity(intent);

finish();

}

// 下载程序

private Uri downLoad() {

URL url = null;

File file = null;

try {

// 下载盛付通手机版

url = new URL(

"http://spm.shengpay.com/apk/ShengPay-release.apk");

HttpURLConnection con = (HttpURLConnection) url

.openConnection();

int fileLength = con.getContentLength();

progressDialog.setDMax(fileLength);// 设置文件大小

InputStream in = con.getInputStream();

file = new File(context.getCacheDir(), "ShengPay-release.apk");

if (!file.exists()) {

file.createNewFile();

}

// 以下是设置权限，不然没有权限去解压会报没权限：

// Unable to open zip

// '/data/data/com.figo.helloworld/cache/ShengPay-release.apk':

// Permission denied

Runtime.getRuntime()

.exec("chmod 777 " + file.getAbsolutePath());

FileOutputStream out = new FileOutputStream(file);

byte[] bytes = new byte[1024];

int c;

int count = 0;

while ((c = in.read(bytes)) != -1) {

out.write(bytes, 0, c);

if (c < 1024) {

publishProgress(count * 1024 + c);

} else {

count++;

publishProgress(count * 1024);

}

in.close();

out.close();

} catch (Exception e) {

e.printStackTrace();

}

return Uri.fromFile(file);

// return flag;

}

// 按钮点击事件

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.btncustom:

progressDialog = new DownloadProgressDialog(this);

progressDialog.setTitle("文件下载");

progressDialog.show();

// 执行任务

new DownLoadTask().execute();

break;

}

第四步、AndroidManifest.xml注册Activity

<intent-filter>

</intent-filter>

</activity>

第五步、运行效果