今天说一下Android中下载App到手机中并自动安装，啥也不说了先上效果图了！
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上面呢是下载中的一个图片和下载后会自动提示你安装的一个图片，二话不说，这接开代码吧！
首先来一个下布局：
<?xml version="1.0" encoding="utf-8"?>
布局随便写了，只要是你想要的布局
然后我么来一个接口，用来帮助我么将要写的下载工具类传输数据的：
package Download;
public interface DownloadListener {
void startDownload();
void stopDownload();
void finishDownload();
void downloadProgress(long progress);
} 这个接口写了4个接口方法，分别是开始下载、停止下载、完成下载以及下载是的进度。
接下来就是写下载工具类了，下载呢就使用OkHttp进行请求网络数据了，这里把这个工具类写成单利模式，方便使用！
package Download;
import android.text.TextUtils;
import android.util.Log;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.ResponseBody;
public class DownloadUtils {
private static volatile DownloadUtils instance;
private final OkHttpClient client;
private DownloadListener mlistener;
private File file;
private String fileAbsolutePath;
public File downloadFile;
private long startPosition;
private Call call;
public DownloadUtils() {
client = new OkHttpClient();
}
public void setListener(DownloadListener listener) {
this.mlistener = listener;
}
/**
* 初始化下载父路径
* @return
*/
public void initDownload(String path) {
file = new File(path);
if(!file.getParentFile().exists()) {
file.getParentFile().mkdir();
}
if(!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
fileAbsolutePath = file.getAbsolutePath();
Log.d("zzz",fileAbsolutePath.toString());
}
public static DownloadUtils getInstance() {
if(instance == null) {
synchronized (DownloadUtils.class) {
if(instance == null) {
instance = new DownloadUtils();
}
}
}
return instance;
}
public void startDownload(String url) {
if(TextUtils.isEmpty(url)) {
return ;
}
if(url.contains(".")) {
String typename = url.substring(url.lastIndexOf(".") + 1);
if(url.contains("/")) {
String filename = url.substring(url.lastIndexOf("/") + 1, url.lastIndexOf("."));
String fn = filename+"."+typename;
downloadFile = new File(this.file, fn);
Log.d("zzz","downloadFile"+downloadFile.toString());
}
}
startPosition = 0;
if(downloadFile.exists()) {
startPosition = downloadFile.length();
}
final Request request = new Request.Builder()
.addHeader("RANGE","bytes="+startPosition+"-")
.url(url)
.build();
call = client.newCall(request);
call.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
mlistener.startDownload();
ResponseBody body = response.body();
// startPosition
long totalLength = body.contentLength() ;
Log.d("zzz", "totalLength: " + totalLength + "----");
InputStream is = body.byteStream();
byte[] bytes = new byte[2048];
int len = 0;
long totalNum = startPosition;
RandomAccessFile raf = new RandomAccessFile(downloadFile, "rw");
while ((len = is.read(bytes,0,bytes.length)) != -1) {
raf.seek(totalNum);
raf.write(bytes,0,len);
totalNum +=len;
mlistener.downloadProgress(totalNum * 100 / totalLength);
}
mlistener.finishDownload();
body.close();
}
});
}
public void stopDownload() {
mlistener.startDownload();
if(call != null && call.isExecuted()) {
call.cancel();
}
}
}
这里做断点下载是使用了RandomAccessFile,大家可以网上去了解一下RandomAccessFile的作用。
下面是主界面的功能实现和调用，基本就是些获取控件和调用刚才写好的工具类：
package zhangtao.bwie.com.continutransform;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import java.io.File;
import Download.DownloadListener;
import Download.DownloadUtils;
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private TextView pro_text;
private Button start_btn;
private Button stop_btn;
private String downloadUrl = "http://d.988wan.com/zft/qmzft32_988wan_01.apk";
private String path = "/ZhangTao/";
private ProgressBar pro_bar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
setOnClick();
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
File storageDirectory = Environment.getExternalStorageDirectory();
final String absolutePath = storageDirectory.getAbsolutePath();
path = absolutePath + path;
DownloadUtils.getInstance().initDownload(path);
DownloadUtils.getInstance().setListener(new DownloadListener() {
@Override
public void startDownload() {
}
@Override
public void stopDownload() {
}
@Override
public void finishDownload() {
File downloadFile = DownloadUtils.getInstance().downloadFile;
installApk(downloadFile);
}
@Override
public void downloadProgress(final long progress) {
runOnUiThread(new Runnable() {
@Override
public void run() {
pro_bar.setProgress((int) progress);
pro_text.setText(progress+"%");
}
});
}
});
}
}
private void initView() {
pro_text = (TextView) findViewById(R.id.pro_text);
start_btn = (Button) findViewById(R.id.start_btn);
stop_btn = (Button) findViewById(R.id.stop_btn);
pro_bar = (ProgressBar) findViewById(R.id.progress);
}
private void setOnClick() {
start_btn.setOnClickListener(this);
stop_btn.setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.start_btn:
DownloadUtils.getInstance().startDownload(downloadUrl);
break;
case R.id.stop_btn:
DownloadUtils.getInstance().stopDownload();
break;
}
}
/**
* 安装apk
* @param file
*/
private void installApk(File file) {
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.addCategory("android.intent.category.DEFAULT");
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");
startActivity(intent);
android.os.Process.killProcess(android.os.Process.myPid());
}
} 上面的自动安装是installApk这个方法，这个没必要去了解太多，都是Android的一个固定方法，一般网上都会有的，希望可以帮到大家！
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持创新互联。
