Android TextView.SetText(int resid)如何工作？

Question

这是Big Nerd Ranch指南中的一个例子:

package com.example.geoquiz;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class QuizActivity extends ActionBarActivity {
    private Button mTrueButton;
    private Button mFalseButton;
    private Button mNextButton;
    private TextView mQuestionTextView;
    private TrueFalse[] mQuestionBank = new TrueFalse[] {
            new TrueFalse(R.string.question_africa, true),
            new TrueFalse(R.string.question_americas, false),
            new TrueFalse(R.string.question_asia, false),
            new TrueFalse(R.string.question_mideast, true),
            new TrueFalse(R.string.question_oceans, true)
    };
    private int mCurrentIndex = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_quiz);
        mTrueButton = (Button)findViewById(R.id.true_button);
        mFalseButton = (Button)findViewById(R.id.false_button);
        mTrueButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Toast.makeText(QuizActivity.this, R.string.incorrect_toast, Toast.LENGTH_SHORT).show();
            }
        });
        mFalseButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Toast.makeText(QuizActivity.this, R.string.correct_toast, Toast.LENGTH_SHORT).show();
            }
        });

        mQuestionTextView = (TextView)findViewById(R.id.question_text_view);
        int question = mQuestionBank[mCurrentIndex].getQuestion();
        mQuestionTextView.setText(question);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.quiz, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

有问题的部分是这样的:

    int question = mQuestionBank[mCurrentIndex].getQuestion();
    mQuestionTextView.setText(question);

question在int这里,我想知道这是如何运作的.更奇怪的是,如果我更改question为文字int,例如1,那么应用程序将无法工作.

Answer 1

我认为这些文档描述得更好,所以我不确定他们最近是否更改了它们(或者我上次查看过).

无论如何,当你提供一个int作为param它指的是一个resource id.所以,如果你有一个string resource,strings.xml你可以在这里提供它而不是文字String.

所以,如果strings.xml你有你的话

<resources>
    <string name="hello">Hello!</string>
</resources>

你能做到的

myTV.setText(R.string.hello);

并myTV会显示"你好".

当你传递它int与idin 不匹配时,R.strings你得到了异常.