新對話框活動未在Android中啟動

Question

我有一個活動，長按列表項時會啟動對話框。 我通過以下代碼片段開始活動：

private void showWifiSettings(int arg2) {
                Intent newIntent = new Intent("com.example.searchingwifi.DIALOGACTIVITY");
                startActivity(newIntent);
                }

並且，新的Dialog活動中的代碼已簽名。

package com.example.searchingwifi;

import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.view.LayoutInflater;

public class DialogActivity extends DialogFragment{


    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        // Get the layout inflater
        LayoutInflater inflater = getActivity().getLayoutInflater();

        // Inflate and set the layout for the dialog
        // Pass null as the parent view because its going in the dialog layout
        builder.setView(inflater.inflate(R.layout.dialog, null));


        return builder.create();
    }
}

長按相應的列表項時，Logcat給我以下錯誤，並且應用程序停止運行。

06-27 12:54:22.150: E/AndroidRuntime(25118): FATAL EXCEPTION: main
06-27 12:54:22.150: E/AndroidRuntime(25118): Process: com.example.searchingwifi, PID: 25118
06-27 12:54:22.150: E/AndroidRuntime(25118): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.searchingwifi/com.example.searchingwifi.DialogActivity}: java.lang.ClassCastException: com.example.searchingwifi.DialogActivity cannot be cast to android.app.Activity
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.app.ActivityThread.access$800(ActivityThread.java:135)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.os.Handler.dispatchMessage(Handler.java:102)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.os.Looper.loop(Looper.java:136)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.app.ActivityThread.main(ActivityThread.java:5017)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at java.lang.reflect.Method.invokeNative(Native Method)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at java.lang.reflect.Method.invoke(Method.java:515)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at dalvik.system.NativeStart.main(Native Method)
06-27 12:54:22.150: E/AndroidRuntime(25118): Caused by: java.lang.ClassCastException: com.example.searchingwifi.DialogActivity cannot be cast to android.app.Activity
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
06-27 12:54:22.150: E/AndroidRuntime(25118):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
06-27 12:54:22.150: E/AndroidRuntime(25118):    ... 11 more

誰能幫助我解決錯誤，我在哪里出錯？

編輯：-即使只是開始一個新的對話框活動，系統仍然會給出錯誤。 LogCat如下所示。

06-30 03:54:10.550: E/AndroidRuntime(1175): FATAL EXCEPTION: main
06-30 03:54:10.550: E/AndroidRuntime(1175): Process: com.example.testingdialog, PID: 1175
06-30 03:54:10.550: E/AndroidRuntime(1175): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.testingdialog/com.example.testingdialog.MainActivity}: java.lang.ClassCastException: com.example.testingdialog.MainActivity cannot be cast to android.app.Activity
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.os.Handler.dispatchMessage(Handler.java:102)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.os.Looper.loop(Looper.java:136)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.app.ActivityThread.main(ActivityThread.java:5017)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at java.lang.reflect.Method.invokeNative(Native Method)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at java.lang.reflect.Method.invoke(Method.java:515)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at dalvik.system.NativeStart.main(Native Method)
06-30 03:54:10.550: E/AndroidRuntime(1175): Caused by: java.lang.ClassCastException: com.example.testingdialog.MainActivity cannot be cast to android.app.Activity
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
06-30 03:54:10.550: E/AndroidRuntime(1175):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
06-30 03:54:10.550: E/AndroidRuntime(1175):     ... 11 more

Answer 1

您應該檢查以下內容： http : //developer.android.com/guide/topics/ui/dialogs.html#ShowingADialog

對話與活動不同。

目前您必須擁有

public class MainActivity extends Activity{
...

更改為

public class MainActivity extends FragmentActivity{
...

然后為了顯示對話框，在FragmentActivity中添加此代碼

public void showDialog() {
DialogActivity newDialog = new DialogActivity();
newDialog.show(getSupportFragmentManager(), "myDialog");

}

提示：不要像DialogActivity這樣調用自定義Dialog類，而要像MyCustomDialog這樣調用（不要在類名中使用“ Activity”）

Answer 2

在這里，您將打開DialogFragment。 請嘗試以下代碼。

DialogFragment newFragment = new DialogActivity();
newFragment.show(getFragmentManager(), "dialog");

希望對你有幫助

更新：在這里您設置LayoutInflator而不是視圖。 這就是為什么它給輸入參數錯誤。 請嘗試以下方法：

@Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        // Get the layout inflater
        View view = getActivity().getLayoutInflater().inflate(R.layout.dialog, null);
        builder.setView(view);

        return builder.create();
    }
}

Answer 3

您正在嘗試啟動實際上是DialogFragment活動。 將其設置為DialogActivity並以如下所示的活動開始：

Intent intent=new Intent(getApplicationContext(), DialogActivity.class);
startActivity(intent);

要么

您可以將其僅保留為Dialogragment ，並顯示為dialogfragment，而不是開始新的活動。

例：

MyDialogFragment myDialogFragment = new MyDialogFragment();
myDialogFragment.show(fragManager, "myDialogFragment");

參考鏈接：

對話框片段示例

對話框活動示例