如何在后台服务中使用alertDialog

Question

我需要在后台服务中提示一个alertDialog，但是它被错误的上下文崩溃了，我该如何处理，我在哪里可以得到正确的上下文？

Answer 1

1、必须设置：mDialog.getWindow().setType( WindowManager.LayoutParams.TYPE_SYSTEM_ALERT); 2、设置权限：

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

Answer 2

代码在 Service class 到 open AlertDialog

private void showAlertDialog() {

        KeyguardManager km = (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);
        KeyguardManager.KeyguardLock kl = km.newKeyguardLock("MyKeyguardLock");
            kl.disableKeyguard();

            PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
            WakeLock wakeLock = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK| PowerManager.ACQUIRE_CAUSES_WAKEUP
                    | PowerManager.ON_AFTER_RELEASE, "MyWakeLock");
            wakeLock.acquire();


        final CharSequence[] items = { getString(R.string.test1), getString(R.string.tes2), getString(R.string.test3), getString(R.string.cancel) };
        AlertDialog.Builder builder = new AlertDialog.Builder(getApplicationContext());
        builder.setTitle("Title");
        builder.setItems(items, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int item) {
                if (items[item].equals(getString(R.string.test1))) {
                    dialog.dismiss();

                } else if (items[item].equals(getString(R.string.test2))) {
                    dialog.dismiss();

                } else if (items[item].equals(getString(R.string.test3))) {

                }else if (items[item].equals(getString(R.string.cancel))) {
                    dialog.dismiss();


                }
            }
        });

        alert = builder.create();
        alert.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
        alert.getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON|
                WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD|
                WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED|
                WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);


        alert.show();

        alert.setOnDismissListener(new OnDismissListener() {

            @Override
            public void onDismiss(DialogInterface arg0) {

            }
        });


        alert.setOnCancelListener(new OnCancelListener() {

            @Override
            public void onCancel(DialogInterface dialog) {

            }
        });


    }

您必须在清单文件

中添加权限

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

您可以根据需要对警报对话框进行自定义。

完成

Answer 3

已接受的答案不适用于 Oreo+ 请在 WindowManager.LayoutParams 中使用标志 TYPE_APPLICATION_OVERLAY 而不是 TYPE_PHONE 或 SYSTEM_ALERT：使用

WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY

改为

WindowManager.LayoutParams.TYPE_SYSTEM_ALERT

叠加层仍然不显示？然后检查你的应用是否有权限

Settings.canDrawOverlays() 如果这是假的那么。

用户也应该有这个权限！ 这是在 Marshmallow

中引入的

// 检查是否 Android M 或更高

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

// Show alert dialog to the user saying a separate permission is 
 needed
    // Launch the settings activity if the user prefers
    Intent myIntent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
    startActivity(myIntent);
}

如何在后台服务中使用alertDialog

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