添加Splash Screen后setPositiveButton文本不显示问题排查

为应用添加启动页（Splash Screen）后，AlertDialog中setPositiveButton设置的“Finish”文本消失，对应位置仅显示空白，但点击该空白区域仍能正常执行finishQuiz()方法。

启动页代码（SplashScreen.java） #

package com.example.numbers;

import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;

import androidx.appcompat.app.AppCompatActivity;

public class SplashScreen extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                startActivity(new Intent(SplashScreen.this, MainActivity.class));
                finish();
            }
        }, 7000);

    }
}

主页面代码（MainActivity.java） #

package com.example.numbers;

import android.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import android.content.DialogInterface;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
    TextView questionTextView;
    TextView totalQuestionTextView;
    Button ansA,ansB,ansC,ansD;
    Button btn_submit;

    int score=0;
    int totalQuestion = QuestionAnswer.question.length;
    int currentQuestionIndex =0;
    String selectedAnswer="";

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        totalQuestionTextView = findViewById(R.id.total_question);
        questionTextView = findViewById(R.id.question);
        ansA = findViewById(R.id.ans_a);
        ansB = findViewById(R.id.ans_b);
        ansC= findViewById(R.id.ans_c);
        ansD = findViewById(R.id.ans_d);
        btn_submit = findViewById(R.id.btn_submit);

        ansA.setOnClickListener(this);
        ansB.setOnClickListener(this);
        ansC.setOnClickListener(this);
        ansD.setOnClickListener(this);
        btn_submit.setOnClickListener(this);


        totalQuestionTextView.setText("You have "+totalQuestion +" questions to answer");

        loadNewQuestion();
    }

    private void loadNewQuestion(){
        if(currentQuestionIndex == totalQuestion){
            finishQuiz();
            return;
        }
        questionTextView.setText(QuestionAnswer.question[currentQuestionIndex]);
        ansA.setText(QuestionAnswer.choices[currentQuestionIndex][0]);
        ansB.setText(QuestionAnswer.choices[currentQuestionIndex][1]);
        ansC.setText(QuestionAnswer.choices[currentQuestionIndex][2]);
        ansD.setText(QuestionAnswer.choices[currentQuestionIndex][3]);

        selectedAnswer="";

    }

    private void finishQuiz(){
        String passStatus;
        if(score >= totalQuestion*0.6){
            passStatus = "You passed - well done!";
        }else{
            passStatus = "You failed this time - but keep trying!";
        }
        new AlertDialog.Builder(this)
                .setTitle(passStatus)
                .setMessage("You scored "+score+" out of "+totalQuestion)
                .setCancelable(false)
                .setPositiveButton("Finish",
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                moveTaskToBack(true);
                                android.os.Process.killProcess(android.os.Process.myPid());
                                System.exit(1);
                            }
                        })
                .show();
    }


     private void restartQuiz(){
        score = 0;
        currentQuestionIndex=0;
        loadNewQuestion();
    }

    @Override
    public void onClick(View view){
        ansA.setBackgroundColor(Color.WHITE);
        ansB.setBackgroundColor(Color.WHITE);
        ansC.setBackgroundColor(Color.WHITE);
        ansD.setBackgroundColor(Color.WHITE);

        Button clickedButton = (Button) view;

        if(clickedButton.getId() == R.id.btn_submit) {
            if(!selectedAnswer.isEmpty()){
                if(selectedAnswer.equals(QuestionAnswer.correctAnswers[currentQuestionIndex])){
                    score++;
                }else{
                    clickedButton.setBackgroundColor(Color.MAGENTA);
                }
                currentQuestionIndex++;
                loadNewQuestion();
            }else{

            }
        }
        else{
            selectedAnswer=clickedButton.getText().toString();
            clickedButton.setBackgroundColor(Color.YELLOW);
        }
    }

    private class OnClickListener implements DialogInterface.OnClickListener {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {

        }
    }
}

问题截图 #

核心原因 #

MainActivity里自定义了一个空实现的内部类OnClickListener，它实现了DialogInterface.OnClickListener，但这个类名和Activity本身实现的View.OnClickListener重名，导致系统渲染AlertDialog按钮时出现逻辑冲突，进而使按钮文本无法正常显示。启动页代码本身没有问题，只是启动流程的类加载顺序变化触发了这个隐藏的命名冲突。

解决方法 #

直接删除MainActivity底部的这个无用内部类即可：

private class OnClickListener implements DialogInterface.OnClickListener {
    @Override
    public void onClick(DialogInterface dialogInterface, int i) {

    }
}

删除后重新编译运行，AlertDialog的“Finish”按钮文本就能正常显示了。

内容的提问来源于stack exchange，提问作者JesusGirl2000