android windowmanager如何管理窗口层级

WindowManager windowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);

// 创建一个对话框
Dialog dialog = new Dialog(this, R.style.CustomDialog);
dialog.setContentView(R.layout.dialog_layout);

// 设置窗口的布局属性
WindowManager.LayoutParams layoutParams = dialog.getWindow().getAttributes();

// 设置窗口的层级
layoutParams.type = WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY; // 用于悬浮窗
// layoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT; // 用于系统警告框
// layoutParams.type = WindowManager.LayoutParams.TYPE_PHONE; // 用于电话窗口
// layoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ERROR; // 用于系统错误窗口

// 设置窗口的宽高
layoutParams.width = WindowManager.LayoutParams.MATCH_PARENT;
layoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;

// 设置窗口的位置
layoutParams.gravity = Gravity.CENTER;

// 设置窗口是否允许背景透明
layoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
// layoutParams.flags = WindowManager.LayoutParams.FLAG_FULLSCREEN; // 设置全屏

// 设置窗口的层级
layoutParams.priority = WindowManager.LayoutParams.PRIORITY_HIGH; // 设置高优先级

windowManager.addView(dialog, layoutParams);

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

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    if (checkSelfPermission(Manifest.permission.SYSTEM_ALERT_WINDOW) != PackageManager.PERMISSION_GRANTED) {
        requestPermissions(new String[]{Manifest.permission.SYSTEM_ALERT_WINDOW}, REQUEST_CODE);
    }
}