Java 我试图将一个活动中的用户输入存储到另一个活动中的listview。这行不通

我一直试图将数据作为单独的项存储到

列表视图中，但它就是不起作用。如果有人谁了解Android Studio和我的问题可以帮助我，我会很有帮助。我认为MainActivity.java中的组织可能是它无法工作的原因。MainActivity.java具有
ListView
，而
NewTask.java
是用户输入任务名称及其到期日期等数据的地方。我已经使用了
startActivityForResult（）
，但仍然存在问题。请帮忙

MainActivity.java

package com.example.shaan.todoer;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;


public class MainActivity extends Activity {

ArrayList<String> list = new ArrayList<String>();

ArrayAdapter<String> adapter;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //Things still left to do:
    //Prevent Overriding of Items
    //Activate Delete Tasks on Hard Click of Items
    //Fit Name, Date, and Priority on One Line of List
    //Attempt to be able to sort items in Listview

    Button firstButton = (Button) findViewById(R.id.add_task_group);

    firstButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, CalendarViewActivity.class));
        }
    });
}

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, list);
        ListView listViewToDo = (ListView) findViewById(R.id.listViewToDo);
        listViewToDo.setAdapter(adapter);
        Intent i = new Intent(this, NewTask.class);
        startActivityForResult(i, 1);
        if(requestCode == 1) {
            if(resultCode == RESULT_OK) {
                String str = data.getStringExtra("type_task_name");
                String str1 = data.getStringExtra("text_date");
                int seek = data.getIntExtra("seekBar", 0);

                adapter.add(str);
            }
            adapter.notifyDataSetChanged();
        }
    }

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

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

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

    // your data from which Activity you called it.
    Bundle data = getIntent().getExtras();
    if (data != null) {
       String str = data.getString("type_task_name");
       String str1 = data.getString("text_date");
        int value = data.getInt("seekBar");
     }
  // now do whatever you want to do with this data

您不需要在onActivityResults中获取数据，因为当您返回到您的活动时它会调用。如果您的活动在堆栈中是新的，那么您可以在onCreate方法中获取它的bumndle数据，因此对于下面的代码-

NewTask.java

package com.example.shaan.todoer;

import java.util.Calendar;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;
import android.widget.Toast;


public class NewTask extends Activity implements OnClickListener {
Button set_date;

private int calYear, calMonth, calDay;
private SeekBar slider;
private TextView sliderLevel;


public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_new_task);
    initialize();

    Button cancel_new_task = (Button) findViewById(R.id.cancel_new_task);
    cancel_new_task.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(NewTask.this, MainActivity.class));
        }
    });

    sliderLevel.setText("Priority Level: " + slider.getProgress() + "/" + slider.getMax());
    slider.setOnClickListener(this);
    slider.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
        int work = 0;

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
            work = progress;
            Toast.makeText(getApplicationContext(), "Priority Level is Changing", Toast.LENGTH_SHORT);
        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
            Toast.makeText(getApplicationContext(), "Started tracking Slider", Toast.LENGTH_SHORT);

        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            sliderLevel.setText("Priority Level: " + work + "/" + slider.getMax());
            Toast.makeText(getApplicationContext(), "Stopped tracking Slider", Toast.LENGTH_SHORT);
        }



    });


}

private void initialize() {
    slider = (SeekBar) findViewById(R.id.seekBar);
    sliderLevel = (TextView) findViewById(R.id.textView7);
    set_date = (Button) findViewById(R.id.set_date);
    text_date = (EditText) findViewById(R.id.text_date);
    set_date.setOnClickListener(this);
    text_date.setOnClickListener(this);
    create_task = (Button) findViewById(R.id.create_task);
    type_task_name = (EditText) findViewById(R.id.type_task_name);
    seekBar = (SeekBar) findViewById(R.id.seekBar);
    text_date = (EditText) findViewById(R.id.text_date);

}

Button create_task;
EditText type_task_name;
SeekBar seekBar;
EditText text_date;


@Override
public void onClick(View v) {
    if (v == set_date) {
        final Calendar cal = Calendar.getInstance();
        calYear = cal.get(Calendar.YEAR);
        calMonth = cal.get(Calendar.MONTH);
        calDay = cal.get(Calendar.DAY_OF_MONTH);

        DatePickerDialog date = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {

            @Override
            public void onDateSet(DatePicker look, int year, int month, int day) {
                text_date.setText((month + 1) + "/" + (day) + "/" + year);

            }
        }, calYear, calMonth, calDay);
        date.show();
    }
}

public void buttonAddClick(View v) {
    startActivity(new Intent(NewTask.this, MainActivity.class));
    Intent i = new Intent();
    i.putExtra("type_task_name", type_task_name.getText().toString());
    i.putExtra("text_date", text_date.getText().toString());
    i.putExtra("seekBar", seekBar.getProgress());
    setResult(RESULT_OK, i);
    finish();
}
}

public void buttonAddClick(View v) {

    Intent i = new Intent(NewTask.this, MainActivity.class);
    i.putExtra("type_task_name", type_task_name.getText().toString());
    i.putExtra("text_date", text_date.getText().toString());
    i.putExtra("seekBar", seekBar.getProgress());
    startActivity(i);

}

在MainActivity.java中

package com.example.shaan.todoer;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;


public class MainActivity extends Activity {

ArrayList<String> list = new ArrayList<String>();

ArrayAdapter<String> adapter;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //Things still left to do:
    //Prevent Overriding of Items
    //Activate Delete Tasks on Hard Click of Items
    //Fit Name, Date, and Priority on One Line of List
    //Attempt to be able to sort items in Listview

    Button firstButton = (Button) findViewById(R.id.add_task_group);

    firstButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, CalendarViewActivity.class));
        }
    });
}

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, list);
        ListView listViewToDo = (ListView) findViewById(R.id.listViewToDo);
        listViewToDo.setAdapter(adapter);
        Intent i = new Intent(this, NewTask.class);
        startActivityForResult(i, 1);
        if(requestCode == 1) {
            if(resultCode == RESULT_OK) {
                String str = data.getStringExtra("type_task_name");
                String str1 = data.getStringExtra("text_date");
                int seek = data.getIntExtra("seekBar", 0);

                adapter.add(str);
            }
            adapter.notifyDataSetChanged();
        }
    }

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

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

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

    // your data from which Activity you called it.
    Bundle data = getIntent().getExtras();
    if (data != null) {
       String str = data.getString("type_task_name");
       String str1 = data.getString("text_date");
        int value = data.getInt("seekBar");
     }
  // now do whatever you want to do with this data

您不需要在onActivityResults中获取数据，因为当您返回到您的活动时它会调用。如果您的活动在堆栈中是新的，那么您可以在onCreate方法中获取它的bumndle数据，因此对于下面的代码-

NewTask.java

package com.example.shaan.todoer;

import java.util.Calendar;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;
import android.widget.Toast;


public class NewTask extends Activity implements OnClickListener {
Button set_date;

private int calYear, calMonth, calDay;
private SeekBar slider;
private TextView sliderLevel;


public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_new_task);
    initialize();

    Button cancel_new_task = (Button) findViewById(R.id.cancel_new_task);
    cancel_new_task.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(NewTask.this, MainActivity.class));
        }
    });

    sliderLevel.setText("Priority Level: " + slider.getProgress() + "/" + slider.getMax());
    slider.setOnClickListener(this);
    slider.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
        int work = 0;

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
            work = progress;
            Toast.makeText(getApplicationContext(), "Priority Level is Changing", Toast.LENGTH_SHORT);
        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
            Toast.makeText(getApplicationContext(), "Started tracking Slider", Toast.LENGTH_SHORT);

        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            sliderLevel.setText("Priority Level: " + work + "/" + slider.getMax());
            Toast.makeText(getApplicationContext(), "Stopped tracking Slider", Toast.LENGTH_SHORT);
        }



    });


}

private void initialize() {
    slider = (SeekBar) findViewById(R.id.seekBar);
    sliderLevel = (TextView) findViewById(R.id.textView7);
    set_date = (Button) findViewById(R.id.set_date);
    text_date = (EditText) findViewById(R.id.text_date);
    set_date.setOnClickListener(this);
    text_date.setOnClickListener(this);
    create_task = (Button) findViewById(R.id.create_task);
    type_task_name = (EditText) findViewById(R.id.type_task_name);
    seekBar = (SeekBar) findViewById(R.id.seekBar);
    text_date = (EditText) findViewById(R.id.text_date);

}

Button create_task;
EditText type_task_name;
SeekBar seekBar;
EditText text_date;


@Override
public void onClick(View v) {
    if (v == set_date) {
        final Calendar cal = Calendar.getInstance();
        calYear = cal.get(Calendar.YEAR);
        calMonth = cal.get(Calendar.MONTH);
        calDay = cal.get(Calendar.DAY_OF_MONTH);

        DatePickerDialog date = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {

            @Override
            public void onDateSet(DatePicker look, int year, int month, int day) {
                text_date.setText((month + 1) + "/" + (day) + "/" + year);

            }
        }, calYear, calMonth, calDay);
        date.show();
    }
}

public void buttonAddClick(View v) {
    startActivity(new Intent(NewTask.this, MainActivity.class));
    Intent i = new Intent();
    i.putExtra("type_task_name", type_task_name.getText().toString());
    i.putExtra("text_date", text_date.getText().toString());
    i.putExtra("seekBar", seekBar.getProgress());
    setResult(RESULT_OK, i);
    finish();
}
}

public void buttonAddClick(View v) {

    Intent i = new Intent(NewTask.this, MainActivity.class);
    i.putExtra("type_task_name", type_task_name.getText().toString());
    i.putExtra("text_date", text_date.getText().toString());
    i.putExtra("seekBar", seekBar.getProgress());
    startActivity(i);

}

在MainActivity.java中

package com.example.shaan.todoer;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;


public class MainActivity extends Activity {

ArrayList<String> list = new ArrayList<String>();

ArrayAdapter<String> adapter;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //Things still left to do:
    //Prevent Overriding of Items
    //Activate Delete Tasks on Hard Click of Items
    //Fit Name, Date, and Priority on One Line of List
    //Attempt to be able to sort items in Listview

    Button firstButton = (Button) findViewById(R.id.add_task_group);

    firstButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, CalendarViewActivity.class));
        }
    });
}

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, list);
        ListView listViewToDo = (ListView) findViewById(R.id.listViewToDo);
        listViewToDo.setAdapter(adapter);
        Intent i = new Intent(this, NewTask.class);
        startActivityForResult(i, 1);
        if(requestCode == 1) {
            if(resultCode == RESULT_OK) {
                String str = data.getStringExtra("type_task_name");
                String str1 = data.getStringExtra("text_date");
                int seek = data.getIntExtra("seekBar", 0);

                adapter.add(str);
            }
            adapter.notifyDataSetChanged();
        }
    }

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

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

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

    // your data from which Activity you called it.
    Bundle data = getIntent().getExtras();
    if (data != null) {
       String str = data.getString("type_task_name");
       String str1 = data.getString("text_date");
        int value = data.getInt("seekBar");
     }
  // now do whatever you want to do with this data

请尝试链接。抱歉，您的链接无法帮助我。由于某种原因，当我输入所有数据并单击某个按钮时，它不会将其发送到列表视图，尽管我没有发现我的代码@NKushwahTry链接有任何错误。很抱歉，您的链接没有帮助我。由于某种原因，当我输入所有数据并单击某个按钮时，它不会将其发送到列表视图，尽管我没有发现我的代码@NKushwahTry链接有任何错误。很抱歉，您的链接没有帮助我。出于某种原因，当我输入所有数据并单击某个按钮时，它不会将其发送到listview，尽管我没有发现我的代码@NKushwah有任何错误