Android 应用在后台弹出提示相关的笔记1

记录在安卓应用中，应用在后台是弹出对话框或显示一个view在前台界面上相关方法以及参数，效果。

int windowType

对话框的设置

final AlertDialog dialog = new AlertDialog.Builder(this).setMessage("test dialog").create(); dialog.getWindow().setType(windowType);
直接显示一个自定义view的设置

final WindowManager.LayoutParams alertParams = new WindowManager.LayoutParams(); alertParams.type = windowType; alertParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE; alertParams.width = WindowManager.LayoutParams.MATCH_PARENT; alertParams.height = 300; alertParams.format = PixelFormat.RGBA_8888; final WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE); final TextView view = new TextView(getApplicationContext()); view.setBackgroundColor(Color.YELLOW); view.setText("test"); wm.addView(view, alertParams);//显示view

实现方式是这样子的：一共2个Activity,1个Service

MainActivity onCreate中的代码：

final AlertDialog dialog = new AlertDialog.Builder(getApplicationContext()).setMessage("test activity1 dialog").create(); dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT); final WindowManager.LayoutParams alertParams = new WindowManager.LayoutParams(); alertParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT; alertParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE; alertParams.width = WindowManager.LayoutParams.MATCH_PARENT; alertParams.height = 300; alertParams.format = PixelFormat.RGBA_8888; final WindowManager wm = (WindowManager) getApplicationContext().getSystemService(Context.WINDOW_SERVICE); final TextView view = new TextView(getApplicationContext()); view.setBackgroundColor(Color.BLUE); view.setText("test"); view.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { wm.removeView(v); } }); new Handler().postDelayed(new Runnable() { @Override public void run() { wm.addView(view, alertParams); dialog.show(); } }, 5000); startService(new Intent(this, Test1Service.class)); startActivity(new Intent(this,Test2Activity.class));
Test1Service的主要代码：

final AlertDialog dialog = new AlertDialog.Builder(this).setMessage("test service dialog").create(); dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT); final WindowManager.LayoutParams alertParams = new WindowManager.LayoutParams(); alertParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT; alertParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE; alertParams.width = WindowManager.LayoutParams.MATCH_PARENT; alertParams.height = 300; alertParams.format = PixelFormat.RGBA_8888; final WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE); final TextView view = new TextView(getApplicationContext()); view.setBackgroundColor(Color.YELLOW); view.setText("test"); view.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { wm.removeView(v); } }); final Handler handler = new Handler(); handler.postDelayed(new Runnable() { @Override public void run() { wm.addView(view, alertParams); dialog.show(); stopSelf(); } }, 3000);
Test2Activity的代码：

final AlertDialog dialog = new AlertDialog.Builder(this).setMessage("test activity2 dialog").create(); dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT); final WindowManager.LayoutParams alertParams = new WindowManager.LayoutParams(); alertParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT; alertParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE; alertParams.width = WindowManager.LayoutParams.MATCH_PARENT; alertParams.height = 300; alertParams.format = PixelFormat.RGBA_8888; final WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE); final TextView view = new TextView(getApplicationContext()); view.setBackgroundColor(Color.GREEN); view.setText("test2"); view.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { wm.removeView(v); } }); new Handler().postDelayed(new Runnable() { @Override public void run() { Log.i(getPackageName(), "显示 activity2"); wm.addView(view, alertParams); dialog.show(); } }, 7000);

注意黄色背景的地方，有关键的影响。
根据顺序，首先是service的显示，然后MainActivity,最后Test2Activity。

以下所述显示情况为启动后立即返回桌面后的显示情况

1、windowType = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT || WindowManager.LayoutParams.TYPE_SYSTEM_ERROR || WindowManager.LayoutParams.TYPE_TOAST

TYPE_SYSTEM_ALERT 需要权限<uses-permissionandroid:name="android.permission.SYSTEM_ALERT_WINDOW"/>

service显示，MainActivity显示，Test2Activity未显示（在4.4以下版本机型上，出现界面显示异常，不知道是不是在虚拟机中的原因，没有真机测试。。。另外，在5.0以上的机型，Test2Activty的对话框和自定义view都显示了）

根据情况来看，是否在后台能弹出显示，关键就是代码中黄色部分所用的是本身的context还是applicationContext（此处说明下，service不管是用本身还是applicationContext，均能弹出显示），这个解释应该就是应用的窗口和单独activity的窗口关系。

TYPE_SYSTEM_ERROR 会遮罩整个屏幕，包括虚拟的“返回”，“HOME"按键

2、windowType = WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY

该类型在显示后，用户无法点击到显示的对话框以及自定义view，但能点击到所覆盖的控件，即触摸事件穿透过去了

关于应用窗口和activity窗口的关联，有待研究，后面补充几个type的说明