众所周知，Toast必须在UI主线程上才能正常显示，而在Service中是无法获得Acivity的Context的，在service中想显示出Toast只需将show的消息发送给主线程Looper就可以了
Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable() {
public void run() {
Toast.makeText(getApplicationContext(), "存Service is runing!",
Toast.LENGTH_SHORT).show();
}
});
此时便可显示Toast
Dialog的用法与此类似，但是要多加个权限
在manifest中添加此权限以弹出dialog
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
Builder builder = new AlertDialog.Builder(getApplicationContext())
.setIcon(android.R.drawable.ic_dialog_info)
.setTitle("service中弹出Dialog了")
.setMessage("是否关闭dialog？")
.setPositiveButton("确定",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int whichButton) {
}
})
.setNegativeButton("取消",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int whichButton) {
}
});
final AlertDialog dialog = builder.create();
dialog.getWindow().setType(
(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT));
Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable() {
public void run() {
dialog.show();
}
});