Question

从哪里开始.. 我是Android的新手，并尝试为Android创建一个小应用程序，显示时间表（5天8小时），这些将显示为40个方格的表格。用户可以通过选择Day（来自微调器），Time（微调器），添加注释（最多15个字符）并选择背景颜色来添加事件。所有这些都必须添加到字符串数组并发送到主要活动。从那里通过从该字符串数组中获取日期和时间槽值，将使用来自相同字符串数组的文本和背景颜色更新适当的正方形。我已经尝试解决这个问题大约四天了，但是我无法理解这个...这里有一些代码：主要活动：

package com.tt;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button settings = (Button)findViewById(R.id.settings);

        Intent a = getIntent();
        String[] add = a.getStringArrayExtra("strings");

        setContentView(R.layout.activity_main);
        TextView detail = (TextView)findViewById(R.id.m1);
        //detail.setText(notes);

        settings.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                Intent i = new Intent(v.getContext(),Settings.class);
                startActivityForResult(i,0);
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

添加活动：

package com.tt;

import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
import android.content.Intent;

public class Add extends Activity implements OnClickListener, OnCheckedChangeListener {
    String[] DOW;
    String[] time;
    String  clr;
    EditText nts;
    boolean click = true;
    Button save;
    RadioGroup days;
    RadioGroup times;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add);
        initialize();

        DOW = getResources().getStringArray(R.array.DOW);
        Spinner s1 =(Spinner)findViewById(R.id.spinner1);
        ArrayAdapter<String>adapter = new      ArrayAdapter<String>(this,android.R.layout.simple_spinner_dropdown_item,DOW);
        s1.setAdapter(adapter);
        s1.setOnItemSelectedListener(new OnItemSelectedListener() {
            public void onItemSelected(AdapterView<?>arg0,View arg1, int arg2, long arg3) {
                int index = arg0.getSelectedItemPosition();
                Toast.makeText(getBaseContext(), "Chosen Day of the Week is     "+ DOW[index], Toast.LENGTH_SHORT).show();
            }
            @Override
            public void onNothingSelected(AdapterView<?>arg0){
                // nothing
            }
        });
        time = getResources().getStringArray(R.array.time);
        Spinner s2 = (Spinner)findViewById(R.id.spinner2);
        ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item,time);
        s2.setAdapter(adapter2);
        s2.setOnItemSelectedListener(new OnItemSelectedListener() {
            public void onItemSelected(AdapterView<?>arg0,View arg1, int arg2, long arg3) {
                int index = arg0.getSelectedItemPosition();
                Toast.makeText(getBaseContext(), "Time is set to "+ time[index], Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {
                // nothing
            }
        });
    }
    private void initialize() {
        save = (Button)findViewById(R.id.save);
        save.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                String notes = nts.getText().toString();
                String day = DOW.toString();
                String tim = time.toString();
                //String color = clr.

                Bundle b = new Bundle();
                /*bag.putString("key1", day);
                //bag.putString("key2",tim);
                //bag.putString("key3", notes);
                //bag.putString("key4", color);*/

                /*String[] added = new String[4];
                added[0]=day;
                added[1]=tim;
                added[2]=color;
                added[3]=notes;*/

                //b.putStringArray("key",added);
                String[] added = new String[] {day, tim, notes};
                //b.putStringArray("key", new String[]{day, tim, notes});
                Intent a = new Intent(Add.this, MainActivity.class);
                a.putExtra("strings",added);
                startActivity(a);
            }
        });
        nts = (EditText) findViewById(R.id.notes);
        //days.setOnCheckedChangeListener((OnCheckedChangeListener) this);
        //times.setOnCheckedChangeListener((OnCheckedChangeListener) this);
    }

    @Override
    public void onClick(View arg0) {
        // nothing
    }

    @Override
    public void onCheckedChanged(RadioGroup arg0, int arg1) {
        switch(arg1) {
        case R.id.blue:
            clr = "blue";
            break;
        case R.id.green:
            clr = "green";
            break;
        case R.id.yellow:
            clr = "yellow";
            break;
        case R.id.red:
            clr = "red";
            break;
        }
    }
}

更新

是的...我已经将字符串数组减少到只有一个字符串......这是假设发送数据的代码：

    private void initialize() 
{
    save = (Button)findViewById(R.id.save);
    nts = (EditText) findViewById(R.id.notes);
}   
    public void onClick(View arg0) 
        {
            String notes = nts.getText().toString();
            //String day = DOW.toString();
            //String tim = time.toString();

            Bundle b = new Bundle();
            b.putString("AddedNote", notes);
            Intent a = new Intent(Add.this, MainActivity.class);
            a.putExtras(b);
            startActivity(a);
            /*String[] added = new String[] {notes};
            a.putExtra("strings",added);
            */
        };

和“接收者”：

    public class MainActivity extends Activity
{
String gotNotes;
TextView notes;
   @Override
    public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initialize();
    Button settings = (Button)findViewById(R.id.settings);
    Bundle gotPackage = getIntent().getExtras();
    gotNotes = gotPackage.getString("AddedNote");
    if (gotNotes != "")
    {
    notes.setText(gotNotes);
    }
    else{}


    settings.setOnClickListener(new OnClickListener()
    {



          public void onClick(View v)
         {
              Intent i = new Intent(v.getContext(),Settings.class);
              startActivityForResult(i,0);
         }

    });

   }

    private void initialize() 
   {
    // TODO Auto-generated method stub
    notes = (TextView)findViewById(R.id.m1);
}

@Override
    public boolean onCreateOptionsMenu(Menu menu) 
   {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;

    }

  }

我得到的结果是由java.lang.nullpointerexception引起的：

   gotNotes = gotPackage.getString("AddedNote");

“接收者”活动的

..

Answer 1

这取决于你的活动android：launchMode，我怀疑你有singleTask或类似的东西。在这种情况下，你应该覆盖onNewIntent，你应该在那里接收你的字符串数组的意图。

替代解决方案是将数据存储在共享首选项中，如果需要，可以将其序列化为JSON对象。

protected void onNewIntent(Intent intent) {
   String[] add = a.getStringArrayExtra("strings");
}

将字符串数组从活动1传递到活动2，从字符串数组中获取值并相应地更改布局

1 个答案: