Android service里面启动activity和alertdialog .

启动activity源码:(记得要加上Intent.FLAG_ACTIVITY_NEW_TASK)

1. Intent intent = new Intent();
2. intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
3. intent.setClass(getApplicationContext(),FileBrowserActivity.class);
4. startActivity(intent);

启动alertDialog源码:

1. AlertDialog.Builder builder = new AlertDialog.Builder(this);
2. builder.setMessage("是否接受文件?")
3. .setPositiveButton("是", new DialogInterface.OnClickListener() {
4. @Override
5. publicvoid onClick(DialogInterface dialog, int which) {
7. }
8. }).setNegativeButton("否", new OnClickListener() {
9. @Override
10. publicvoid onClick(DialogInterface dialog, int which) {
11. }
12. });
13. AlertDialog ad = builder.create();
14. // ad.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG); //系统中关机对话框就是这个属性
15. ad.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
16. ad.setCanceledOnTouchOutside(false); //点击外面区域不会让dialog消失
17. ad.show();

还要加上权限 

1. <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

转载于:https://www.cnblogs.com/ada-zheng/archive/2013/01/16/2862737.html