Android中使用广播接收者来弹出对话框的坑

琢磨了老半天，试了一下网上说的一种方法，我发现不行，这种方法是这样的：

1.首先注册静态广播

2.在清单中添加权限

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

3.然后在show()之前设置Dialog类型为TYPE_SYSTEM_ALERT

alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);

然后发现还是不行。这就郁闷啦！网上有人说用动态注册方式可以实现在广播接收者中弹出对话框，于是便试了一下，果然可以

首先开始注册广播，并给广播消息

private BroadcastReceiver broadcastReceiver;

broadcastReceiver=new tipsBroadReciver();
                IntentFilter intentFilter=new IntentFilter();
                intentFilter.addAction(ACTION);
                context.registerReceiver(broadcastReceiver,intentFilter);
                Intent intent=new Intent();
                intent.setAction(ACTION);
                intent.putExtra("state","1");
                context.sendBroadcast(intent);

在广播接收者中打开对话框

 String state=intent.getExtras().getString("state");
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(context);
        dialogBuilder.setTitle("提示");
        if(state.equals("1")){
            text="没有查找到该好友";
        }
        dialogBuilder.setMessage(text);
        dialogBuilder.setCancelable(false);
        dialogBuilder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                context.unregisterReceiver(tipsBroadReciver.this);
            }
        });
        AlertDialog alertDialog = dialogBuilder.create();
        alertDialog.show();