从 onCreate 之外的方法访问 UI

Question

我尝试使用以下方法创建一个类并从 onCreate 之外的函数运行它，但是我尝试执行它时总是收到空指针异常错误。我用谷歌搜索并尝试了一整天没有结果。有人可以帮我理解如何从onCreate之外的方法执行以下类吗？如果我在 Create 中调用它，它运行得很好。谢谢。

  runOnUiThread(new Runnable() {
                @Override
                public void run() {
       Dialog x = new Dialog();
       x.showDialog(this, act0, "restart0");
}
});


//Dialog class
package com.calmchess.game1;

import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.View;
import android.widget.Button;

/**
 * Created by bobsmithzero on 10/16/17.
 */

public class Dialog extends Activity{


    public void showDialog(final Context context, final Activity act00, final String dialogId0) {

        switch (dialogId0) {


            case ("pause0"):
                Button paBtn0 = (Button) act00.findViewById(R.id.pabtn0);
                paBtn0.setOnClickListener(new View.OnClickListener() {


                    public void onClick(View v) {


                        //set up pause dialog
                        final android.app.Dialog dialog0 = new android.app.Dialog(context);
                        dialog0.setContentView(R.layout.activity_controls);
                        dialog0.setCancelable(true);

                        Globals.pause0 = true;


                        Button button = (Button) dialog0.findViewById(R.id.pasbtn0);
                        button.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {


                                dialog0.cancel();
                                Globals.pause0 = false;
                            }
                        });

                        Button reBtn0 = (Button) dialog0.findViewById(R.id.rebtn0);
                        reBtn0.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {

                                Restart restart0 = new Restart();
                                restart0.doRestart(context);
                            }
                        });


                        dialog0.show();
                    }

                });

                break;


            case ("restart0"):
                Log.e("error","this thAT");
                //set up pause dialog
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        //set up pause dialog
                        android.app.Dialog dialog1 = new android.app.Dialog(context);


                        dialog1.setContentView(R.layout.activity_restart);
                        dialog1.setCancelable(true);

                        Globals.pause0 = true;


                        Button button = (Button) dialog1.findViewById(R.id.restart0);
                        button.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {


                                Restart restart0 = new Restart();
                                restart0.doRestart(context);
                            }
                        });


                        dialog1.show();

                    }
                });
                break;
        }



    }
}

Answer 1

在

x.showDialog(this, act0, "restart0");

this 是您的 Runnable 实例。用正确的上下文实例替换 this。以YourActivity.this 为例。