关于DownloadManager的一些问题

来源：互联网发布：webp看图软件编辑：程序博客网时间：2024/05/21 06:46

我们都知道自动升级可以调取安卓系统的downloadManager来完成下载。

我是遇到一个问题，在调游标查询的时候，查询的游标为空，并且下面的download会参数非法异常。

后来经过研究，发现是因为安卓手机的下载管理器有时会关闭，导致我根本查不到下载器，也就没办法下载了

其实我们可以自己写一个的，也不费事，下面贴代码。

public class MainActivity extends Activity implements View.OnClickListener {

private ImageView dong;
private Intent intent;
private Button download;
private static final String URL_STRING = "http://www.shoufangbao.net/download.php?canal=400";
private static int down = 0;
File file;
private Button downlaod;

private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);

switch (msg.what) {
case 1:
download.setText("点击安装");
down = 1;
break;
case 2:
down = 2;
download.setText("打开");
break;
}
}

};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
downlaod = (Button) findViewById(R.id.start);
downlaod.setOnClickListener(this);
if (down != 0) {
down = 0;
}

}

@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.start:
PackageManager manager = this.getPackageManager();
Intent intent = manager.getLaunchIntentForPackage("com.kupangstudio.shoufangbao");
// 下载apk
if (down == 0) {
if (intent == null) {
downFile(URL_STRING);
download.setText("正在下载");
} else {
Toast.makeText(this, "亲，您已经安装该应用，可直接打开。", Toast.LENGTH_SHORT).show();
Message message = handler.obtainMessage();
message.what = 2;
handler.sendMessage(message);
}
// 安装APK
} else if (down == 1) {
installApk();
// 打开apk
} else if (down == 2) {
openApk(this, URL_STRING);
}
break;
default:
break;
}
}

/**
* 后台在下面一个Apk 下载完成后返回下载好的文件
*
* @param httpUrl
* @return
*/
private File downFile(final String httpUrl) {
new Thread(new Runnable() {
@Override
public void run() {
file = getFile();
if (!file.exists()) {
try {
URL url = new URL(httpUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(5000);
FileOutputStream fileOutputStream = null;
InputStream inputStream;
if (connection.getResponseCode() == 200) {
inputStream = connection.getInputStream();

if (inputStream != null) {
file = getFile();
fileOutputStream = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int length = 0;

while ((length = inputStream.read(buffer)) != -1) {
fileOutputStream.write(buffer, 0, length);
}
fileOutputStream.close();
fileOutputStream.flush();
}
inputStream.close();
}

System.out.println("已经下载完成");
// 往handler发送一条消息更改button的text属性
Message message = handler.obtainMessage();
message.what = 1;
handler.sendMessage(message);

} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
} else {
Message message = handler.obtainMessage();
message.what = 1;
handler.sendMessage(message);
}
}
}).start();

return file;
}

// 接收到安装完成apk的广播
BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {

@Override
public void onReceive(Context context, Intent intent) {
System.out.println("接收到安装完成apk的广播");
Message message = handler.obtainMessage();
message.what = 2;
handler.sendMessage(message);
}
};

@Override
public void onStart() {
super.onStart();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(Intent.ACTION_PACKAGE_ADDED);
intentFilter.addDataScheme("package");
// 注册一个广播
this.registerReceiver(broadcastReceiver, intentFilter);
}

@Override
public void onDestroy() {
super.onDestroy();
// 解除广播
this.unregisterReceiver(broadcastReceiver);
}

/**
* 安装APK
*/
private void installApk() {
intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");
startActivity(intent);
}

/**
* 打开已经安装好的apk
*/
private void openApk(Context context, String url) {
/*PackageManager manager = context.getPackageManager();
// 这里的是你下载好的文件路径
Toast.makeText(MainActivity.this,"manager",Toast.LENGTH_SHORT).show();
PackageInfo info = manager.getPackageArchiveInfo(Environment.getExternalStorageDirectory().getAbsolutePath()
+ "shoufangbao.apk", PackageManager.GET_ACTIVITIES);
Toast.makeText(MainActivity.this,"info="+info,Toast.LENGTH_SHORT).show();
if (info != null) {
Intent intent = manager.getLaunchIntentForPackage(info.applicationInfo.packageName);
Toast.makeText(MainActivity.this,"intent",Toast.LENGTH_SHORT).show();
startActivity(intent);
}
*/
PackageManager manager = context.getPackageManager();
Intent intent = manager.getLaunchIntentForPackage("com.kupangstudio.shoufangbao");
startActivity(intent);
}

/**
* 根据传过来url创建文件
*/
private File getFile() {

File files = new File(Environment.getExternalStorageDirectory().getAbsoluteFile(), "shoufangbao.apk");

return files;
}

/* *//**
* 截取出url后面的apk的文件名
*
* @param url
* @return
*//*
private String getFilePath(String url) {
return url.substring(url.lastIndexOf("/"), url.length());
}*/
}

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