Android Training精要(四) Intent注意事项

判断有处理Intent的Activity

PackageManager packageManager = getPackageManager();
List<ResolveInfo> activities = packageManager.queryIntentActivities(mapIntent, 0);
boolean isIntentSafe = activities.size() > 0; 

// Start an activity if it's safe
if (isIntentSafe) {
    startActivity(mapIntent);
}

將可以處理Intent的所有app列表做成下拉選擇框的形式

Intent intent = new Intent(Intent.ACTION_SEND);
// Always use string resources for UI text.
// This says something like "Share this photo with"
String title = getResources().getString(R.string.chooser_title);
// Create and start the chooser
Intent chooser = Intent.createChooser(intent, title);
startActivity(chooser);