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