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(); } });