如何基于一个布尔值通过一个按钮访问两个不同的onclicklisteners

Question

根据用户的选择，我想在按下按钮时打开一个 activity 或另一个。我还尝试仅设置一个 Listener 并在其中设置，具体取决于意图一个 activity 或另一个的布尔值，但这让我遇到了 "Variable is accessed from within inner class, needs to be declared at final " 错误。谢谢！

 but1 = (Button) findViewById(R.id.start);

    RadioButton selectionA = (RadioButton) findViewById(R.id.buttonSelectionA);
    boolean VocabularySelected = selectionA.isChecked();

    RadioButton selectionB = (RadioButton) findViewById(R.id.buttonSelectionB);
    boolean MathSelected = selectionB.isChecked();

    if (VocabularySelected) {
        but1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Intent Vocabulary = new Intent(MainActivity.this, VocabularyActivity.class);
                startActivity(Vocabulary);
            }
        });
    }
    if (MathSelected) {
        but1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Intent Math = new Intent(MainActivity.this, MathActivity.class);
                startActivity(Math);
            }
        });
    }

Answer 1

为什么不使用相同的点击侦听器并在其中根据布尔值执行逻辑？

but1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (MathSelected) {
                Intent Math = new Intent(MainActivity.this, MathActivity.class);
                startActivity(Math);
            } else if(VocabularySelected) {
                Intent Vocabulary = new Intent(MainActivity.this, VocabularyActivity.class);
                startActivity(Vocabulary);
            }
        }
    });

Answer 2

一个视图只能分配一个 OnClickListener，因此您需要检查从侦听器中采用哪条路径。

为避免有关访问非最终变量的错误，您可以以另一种方式执行检查。也许是这样的：

but1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        RadioButton selectionA = (RadioButton) findViewById(R.id.buttonSelectionA);
        RadioButton selectionB = (RadioButton) findViewById(R.id.buttonSelectionB);

        if (selectionA.isChecked()) {
            Intent Vocabulary = new Intent(MainActivity.this, VocabularyActivity.class);
            startActivity(Vocabulary);
        else if (selectionB.isChecked()) {
            Intent Math = new Intent(MainActivity.this, MathActivity.class);
            startActivity(Math);
        }
    }
});

Answer 3

有很多方法可以做到这一点，这是我最喜欢的方法之一，通过在侦听器中引用视图本身：

but1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (((RadioButton) findViewById(R.id.buttonSelectionA)).isChecked()) {
                Intent Vocabulary = new Intent(MainActivity.this, VocabularyActivity.class);
                startActivity(Vocabulary);
            } else if (((RadioButton) findViewById(R.id.buttonSelectionB)).isChecked()) {
                Intent Math = new Intent(MainActivity.this, MathActivity.class);
                startActivity(Math);
            }
        }
    });

它不是最可读的，而是最短的。

您还可以将布尔变量声明为 class 的成员，并在一个侦听器中同时使用它们，如下所示：

public class YourActivity extends AppCompatActivity{
...
    private boolean mVocabularyChecked, mMathChecked;
...
    private void yourMethod() {
        but1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (mVocabularyChecked) {
                    Intent Vocabulary = new Intent(MainActivity.this, VocabularyActivity.class);
                    startActivity(Vocabulary);
                } else if (mMathChecked) {
                    Intent Math = new Intent(MainActivity.this, MathActivity.class);
                    startActivity(Math);
                }
            }
        });
    }

如何基于一个布尔值通过一个按钮访问两个不同的onclicklisteners

How to access two different onclicklisteners with one button based on a boolean

android

buttonclick