文件最後修改時間:
String date = new SimpleDateFormat("yyyy/MM/dd HH:mm")
.format(new Date(file4.lastModified())); 要想重新掃描U盤,可以自己發送u盤插入的廣播
public void reScanVideoFiles() {
Intent intent = new Intent(Intent.ACTION_MEDIA_MOUNTED,
Uri.parse("file://" + ROOT_PATH));
this.sendBroadcast(intent);
}
U盤插入監聽者
@Override
protected void onResume() {
// TODO Auto-generated method stub
IntentFilter intentFilter =
new IntentFilter(Intent.ACTION_MEDIA_MOUNTED);
intentFilter.addAction(Intent.ACTION_MEDIA_EJECT);
intentFilter.addAction(Intent.ACTION_MEDIA_UNMOUNTED);
intentFilter.addAction(Intent.ACTION_SCREEN_OFF);
intentFilter.addDataScheme("file");
registerReceiver(mScanListener, intentFilter);
super.onResume();
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
unregisterReceiver(mScanListener);
super.onPause();
}
private BroadcastReceiver mScanListener = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (Intent.ACTION_MEDIA_UNMOUNTED.equals(action)) {
} else if (Intent.ACTION_MEDIA_SCANNER_STARTED.equals(action)) {
} else if (Intent.ACTION_MEDIA_SCANNER_FINISHED.equals(action)) {
}else if(Intent.ACTION_MEDIA_MOUNTED.equals(action)) {
} else if(Intent.ACTION_MEDIA_EJECT.equals(action)) { }
}
};
HDMI插入 拔出監聽者
private BroadcastReceiver mHDMIPlugReceiver = new BroadcastReceiver()
{
@Override
public void onReceive(Context context, Intent intent)
{
if (WindowManagerPolicy.ACTION_HDMI_HW_PLUGGED.equals(intent.getAction()))
{
boolean plugState = intent.getBooleanExtra(WindowManagerPolicy.EXTRA_HDMI_PLUGGED_STATE,
false);
if(plugState)
{
onPlugHDMI();
}
else
{
onUnplugHDMI();
}
}
}
};
android中獲取網絡圖片是一件耗時的操作，如果直接獲取有可能會出現應用程序無響應（ANR:Application Not Responding）對話框的情況。對於這種情況，一般的方法就是耗時操作用線程來實現。下面列三種獲取url圖片的方法：
1.直接獲取：（容易：ANR，不推薦用）
mImageView = (ImageView)this.findViewById(R.id.imageThreadConcept) ;
Drawable drawable = loadImageFromNetwork(IMAGE_URL);
mImageView.setImageDrawable(drawable) ;
公用方法：
private Drawable loadImageFromNetwork(String imageUrl)
{
Drawable drawable = null;
try {
// 可以在這裏通過文件名來判斷，是否本地有此圖片
drawable = Drawable.createFromStream(
new URL(imageUrl).openStream(), "image.gif");
} catch (IOException e) {
Log.d("test", e.getMessage());
}
if (drawable == null) {
Log.d("test", "null drawable");
} else {
Log.d("test", "not null drawable");
}
return drawable ;
}
2. 後臺線程獲取url圖片：
mImageView = (ImageView)this.findViewById(R.id.imageThreadConcept) ;
new Thread(new Runnable(){
Drawable drawable = loadImageFromNetwork(IMAGE_URL);
@Override
public void run() {
// post() 特別關鍵，就是到UI主線程去更新圖片
mImageView.post(new Runnable(){
@Override
public void run() {
// TODO Auto-generated method stub
mImageView.setImageDrawable(drawable) ;
}}) ;
}
}).start() ;
3.AsyncTask獲取url圖片
mImageView = (ImageView)this.findViewById(R.id.imageThreadConcept) ;
new DownloadImageTask().execute(IMAGE_URL) ;
private class DownloadImageTask extends AsyncTask<String, Void, Drawable>
{
protected Drawable doInBackground(String... urls) {
return loadImageFromNetwork(urls[0]);
}
protected void onPostExecute(Drawable result) {
mImageView.setImageDrawable(result);
}
}
比較三種方法，感覺代碼簡潔方面用第三方法不錯。
