java - 如何更改此 fragment

Question

我有这个fragment1，我想将另一个fragment中的java放在这里。问题是，我导入的 java 来自 MainActivity.java，如果我将其复制过来，它似乎不起作用。我已经为其导入了字符串和 XML，只需要知道如何正确地将 java 导入到其中即可:

当前 fragment

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class ConnectFragment extends Fragment {

public ConnectFragment() {
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_connect, container, false);

    return rootView;
}

}

我要导入的 Java:

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {

public String sign = "";
public String total= "";
public Double tempDouble, tempDouble2;


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

    // Buttons for Felony
    Button button1 =(Button)findViewById(R.id.button1);
    Button button2 =(Button)findViewById(R.id.button2);
    Button button3 =(Button)findViewById(R.id.button3);
    Button button4 =(Button)findViewById(R.id.button4);
    Button button5 =(Button)findViewById(R.id.button5);
    //Buttons for misdemeanors
    Button button6 =(Button)findViewById(R.id.button7);
    Button button7 =(Button)findViewById(R.id.button8);
    Button button8 =(Button)findViewById(R.id.button6);
    //Buttons for Infraction
    Button button9 =(Button)findViewById(R.id.button9);
    //clear, +, =
    Button button10=(Button)findViewById(R.id.button10);
    Button button11 =(Button)findViewById(R.id.button11);
    Button button12 =(Button)findViewById(R.id.button12);




    // button 1 event handler
    button1.setOnClickListener(
            //button 1 interface
            new Button.OnClickListener()
            {
                //Button 1 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("100 years");
                }
            }
    );
    // button 2 event handler
    button2.setOnClickListener(
            //button 2 interface
            new Button.OnClickListener()
            {
                //Button 2 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("25 years");
                }
            }
    );
    // button 3 event handler
    button3.setOnClickListener(
            //button 3 interface
            new Button.OnClickListener()
            {
                //Button 3 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("10 years");
                }
            }
    );
    // button 4 event handler
    button4.setOnClickListener(
            //button 4 interface
            new Button.OnClickListener()
            {
                //Button 4 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("5 years");
                }
            }
    );
    // button 5 event handler
    button5.setOnClickListener(
            //button 5 interface
            new Button.OnClickListener()
            {
                //Button 5 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("1 years");
                }
            }
    );
    // button 6 event handler
    button6.setOnClickListener(
            //button 1 interface
            new Button.OnClickListener()
            {
                //Button 6 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("1 years");
                }
            }
    );
    // button 7 event handler
    button7.setOnClickListener(
            //button 7 interface
            new Button.OnClickListener()
            {
                //Button 7 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("0.5 years");
                }
            }
    );
    // button 8 event handler
    button8.setOnClickListener(
            //button 8 interface
            new Button.OnClickListener()
            {
                //Button 8 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("0.25 years");
                }
            }
    );
    // button 9 event handler
    button9.setOnClickListener(
            //button 9 interface
            new Button.OnClickListener()
            {
                //Button 9 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.append("0.013 years");
                }
            }
    );
    // button 10 event handler
    button10.setOnClickListener(
            //button 10 interface
            new Button.OnClickListener()
            {
                //Button 10 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    output.setText("");
                }
            }
    );
    // button 12 event handler
    button12.setOnClickListener(
            //button 12 interface
            new Button.OnClickListener()
            {
                //Button 12 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    tempDouble = Double.parseDouble(output.getText().toString());
                    output.setText("");
                    sign = "+";
                }
            }
    );

    // button 11 event handler
    button11.setOnClickListener(
            //button 11 interface
            new Button.OnClickListener()
            {
                //Button 11 callback method
                public void onClick(View v)
                {
                    TextView output = (TextView)findViewById(R.id.editText);
                    tempDouble2 = Double.parseDouble(output.getText().toString());
                    if (sign=="+")
                    {
                        output.setText(Double.toString(tempDouble+tempDouble2));
                        sign="";
                    }
                }
            }
    );
}
}

Answer 1

您的代码已损坏，因为您需要执行 rootView.findViewById(R.id.the_item_id) 来获取对所有 UI 组件的引用。

请参阅Fragment API Docs

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_connect, container, false);
    Button aButton = (Button) rootView.findViewById(R.id.button_id);

    return rootView;
}

这会对你有帮助