在向 TextView 添加一些单词后，我尝试使用一个简单的按钮更改 java android 中字符串的某些部分，但它不起作用

Question

before i am start, i add some words using a Button to the TextView, and then i try to change that words, that i add recently to the TextView using a simple Button, but it didn't works

but if i am using default text that i already set up on the TextView(it mean i didn't add any new words to the TextView, and just replace some parts of the words that already there), it works, why is this happen, is anything wrong with my code?, and what is the solution?

sorry my english are pretty bad, it's hard to explain everything in english, hope you all understand what i mean

thanks, here is my code

public class MainActivity extends AppCompatActivity {

private TextView output;
private Button joe, lee, ricele;
private String outputValue;

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

    //name to be added or replace
    joe = findViewById(R.id.joe);
    lee = findViewById(R.id.lee);
    ricele = findViewById(R.id.ricele);

    //get TextView id
    output = findViewById(R.id.output);

    //get String from TextView
    outputValue = output.getText().toString();

    //to added or update the last name to the output(TextView)
    if (!outputValue.contains("ricele")) {
        joe.setOnClickListener(new View.OnClickListener() {
            @SuppressLint("SetTextI18n")
            @Override
            public void onClick(View v) {
                output.append(" ricele");
            }
        });
    }

    //to replace the last name "ricele" to "lee" (but this is didn't work)
    if (outputValue.contains("ricele")) {
        lee.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                outputValue = outputValue.replace("ricele", "lee");
                output.setText(outputValue);
            }
        });
    }
}

Answer 1

Problem in your code that you set onclicklistener only if condition match. You should move if inside on click handler. Something like this

//to added or update the last name to the output(TextView)
        joe.setOnClickListener(new View.OnClickListener() {
            @SuppressLint("SetTextI18n")
            @Override
            public void onClick(View v) {
                String outputValue = output.getText().toString();
                if (!outputValue.contains("ricele")) {
                    output.append(" ricele");
                }
            }
        });

    //to replace the last name "ricele" to "lee" (but this is didn't work)

        lee.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String outputValue = output.getText().toString();
                if (outputValue.contains("ricele")) {
                    outputValue = outputValue.replace("ricele", "lee");
                    output.setText(outputValue);
                }
            }
        });

Answer 2

You have to check the condition inside onClick to append/replace output. In your code either joe.setOnClickListener or lee.setOnClickListener is initiated due to condition. Check below:

//to added or update the last name to the output(TextView)

joe.setOnClickListener(new View.OnClickListener() {
    @SuppressLint("SetTextI18n")
    @Override
    public void onClick(View v) {
        outputValue = output.getText().toString();

        if (!outputValue.contains("ricele")) {
            output.append(" ricele");
        }
    }
});

//to replace the last name "ricele" to "lee"

lee.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        outputValue = output.getText().toString();

        if (outputValue.contains("ricele")) {
            outputValue = outputValue.replace("ricele", "lee");
            output.setText(outputValue);
        }
    }
});

Answer 3

 public void onClick(View v) {
            output.append(" ricele"); // see here is the space you are adding remove that
        }
    });