Android：无法将从文件读取的数据传递给多个类

Question

我在将从文本文件读取的数据传递到应用程序中的另一个类时遇到问题。我可以很好地从文件中读取，但我认为我需要使用 Bundle，但我不知道该怎么做。我想让第二个类处理文本文件中的数据，然后在第一类中显示。

编辑：我已经弄清楚如何使用意图从文件中传递字符串。我仍在努力解决一些错误。

第二次编辑：我知道有一种更有效的方法。我可以让它工作的唯一方法是让 MainActivity 中的第一个按钮使用 startActivity(intent) 来允许 secondActivity 捆绑从文件中读取的字符串。

MainActivity.java：

public class MainActivity extends Activity {

    Button btn;
    Button bReadFile;
    TextView tvRead;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn = (Button) findViewById(R.id.btnNext);
        bReadFile = (Button) findViewById(R.id.btnRead);
        tvRead = (TextView) findViewById(R.id.tvMain);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //trying to find a way to remove this button
                Intent intent = new Intent(MainActivity.this, econdActivity.class);
                startActivity(intent);
            }
        });

        bReadFile.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                String value = getIntent().getExtras().getString("key");
                tvRead.setText(value);
            }
        });
    }
}

secondActivity.java：

public class secondActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent mIntent = new Intent(secondActivity.this, MainActivity.class);
        mIntent.putExtra("key", readDataFile());
        startActivity(mIntent);
    }

    public String readDataFile() {
        String strData = null;
        InputStream is = null;
        try {
            is = getResources().openRawResource(R.raw.data_text);
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            strData = br.readLine();
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return strData;
    }
}

Answer 1

根据您的要求使用以下编辑过的代码 MainActivity.java

public class MainActivity extends Activity {

    Button btn;
    Button bReadFile;
    TextView tvRead;
    String value;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn = (Button) findViewById(R.id.btnNext);
        bReadFile = (Button) findViewById(R.id.btnRead);
        tvRead = (TextView) findViewById(R.id.tvMain);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //trying to find a way to remove this button
                Intent intent = new Intent(MainActivity.this, secondActivity.class);
                startActivityForResults(intent,0);
            }
        });

        bReadFile.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                tvRead.setText(value);
            }
        });
    }
    @Override
   protected void onActivityResult(int requestCode, int resultCode, Intent data){
       value = data.getStringExtra("key");
}
}

secondActivity.java 的代码

public class secondActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Intent i = new Intent();
    i.putExtra("key", readDataFile());
    setResult(RESULT_OK, i);
    finish();
    }

    public String readDataFile() {
        String strData = null;
        InputStream is = null;
        try {
            is = getResources().openRawResource(R.raw.data_text);
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            strData = br.readLine();
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return strData;
    }
}