java - 未知错误 - bundle 字符串数组

Question

每次我按下菜单按钮 --> History 以启动 History.java 类时，我都会收到此应用程序的错误消息。我相当确定它与将两个数组从 TipBookActivity.java 类发送到 History.java 类的 Bundle 方法有关。

下面是 TipBookActivity 代码:

public class TipBookActivity extends Activity {
/** Called when the activity is first created. */

TextView textTip,textHour,textWage;
EditText editHour,editTip;
float wage;
int precision = 100;
String sTip,sHour;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    textTip = (TextView) findViewById(R.id.tvTip);
    textHour = (TextView) findViewById(R.id.tvHour);
    textWage = (TextView) findViewById(R.id.tvWage);
    editTip = (EditText) findViewById(R.id.etTip);
    editHour = (EditText) findViewById(R.id.etHour);
    Button bSubmit = (Button) findViewById(R.id.bSubmit);
    final Bundle bTip = new Bundle();
    final Bundle bHour = new Bundle();
    final ArrayList<String> tipList = new ArrayList<String>();    
    final ArrayList<String> hourList = new ArrayList<String>();
    bSubmit.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            textHour.setText(editHour.getText().toString());
            textTip.setText(editTip.getText().toString());
            wage = Float.parseFloat(textTip.getText().toString()) / Float.parseFloat(textHour.getText().toString());
            String tip = String.format("$%.2f",wage);
            textWage.setText(String.valueOf(tip) + " an hour");     
            textHour.setText(editHour.getText() + " Hour(s)");
            textTip.setText("$" + editTip.getText());
            bTip.putStringArray(sTip,new String[] {editTip.getText().toString()});
            bHour.putStringArray(sHour,new String[] {editHour.getText().toString()});
            tipList.addAll(Arrays.asList(sTip));
            hourList.addAll(Arrays.asList(sHour));
            Intent i = new Intent(TipBookActivity.this,History.class);
            i.putExtras(bTip);
            i.putExtras(bHour);
        }       
    });
}

public boolean onCreateOptionsMenu(Menu menu){
    super.onCreateOptionsMenu(menu);
    MenuInflater mMain = getMenuInflater();
    mMain.inflate(R.menu.main_menu,menu);
    return true;
}

public boolean onOptionsItemSelected(MenuItem item){
    switch (item.getItemId()){
    case R.id.menuHistory:
         startActivity(new Intent("com.smarticle.tipbook.HISTORY"));            
         return true;
    case R.id.menuClear:
        //set up next tutorials
        Toast display = Toast.makeText(this, "Clear History feature coming soon.", Toast.LENGTH_SHORT);
        display.show();
        return true;
    }
    return false;
}
}

历史类代码:

public class History extends Activity{

private ListView mainListViewTip;
private ListView mainListViewHour;
private ArrayAdapter<String>listAdapterTip;
private ArrayAdapter<String>listAdapterHour;
String sTip,sHour;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.history_main);
    Bundle bTip = this.getIntent().getExtras();
    Bundle bHour = this.getIntent().getExtras();
    String[] array1 = bTip.getStringArray(sTip);
    String[] array2 = bHour.getStringArray(sHour);
    ListView mainListViewTip = (ListView) findViewById(R.id.mainListViewTip);
    ListView mainListViewHour = (ListView) findViewById(R.id.mainListViewHour);
    ArrayList<String> tipList = new ArrayList<String>();
    ArrayList<String> hourList = new ArrayList<String>();
    tipList.addAll(Arrays.asList(sTip));
    hourList.addAll(Arrays.asList(sHour));
    listAdapterTip = new ArrayAdapter<String>(this,R.layout.simplerow,tipList);
    listAdapterHour = new ArrayAdapter<String>(this,R.layout.simplerow,hourList);
    mainListViewTip.setAdapter(listAdapterTip);
    mainListViewHour.setAdapter(listAdapterHour);
}

}

如能提供有关识别错误原因的任何帮助，我们将不胜感激。该代码有效(我认为在理论上)，但在实践中行不通。大致思路是在EditText字段中输入两个数字，保存为字符串，显示为TextView，设置为ArrayList，然后打包发送给其他类显示在ListView中。

Answer 1

您没有在两个 Activity 中初始化 sTip 和 sHour 字符串。所以用任何常量值初始化 sTip 和 Shour 字符串:

String sTip="sTip",sHour="sHour";

并且从 TipBookActivity 中你没有将 Intent 传递给 startActivity 所以首先在全局声明 Intent i 然后启动你的 Activity 为:

   TextView textTip,textHour,textWage;
    EditText editHour,editTip;
    float wage;
    int precision = 100;
    String sTip,sHour;
    Intent i; // declare here

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
textTip = (TextView) findViewById(R.id.tvTip);
    textHour = (TextView) findViewById(R.id.tvHour);
    textWage = (TextView) findViewById(R.id.tvWage);
    editTip = (EditText) findViewById(R.id.etTip);
    editHour = (EditText) findViewById(R.id.etHour);
    Button bSubmit = (Button) findViewById(R.id.bSubmit);
    final Bundle bTip = new Bundle();
    final Bundle bHour = new Bundle();
    final ArrayList<String> tipList = new ArrayList<String>();    
    final ArrayList<String> hourList = new ArrayList<String>();
    bSubmit.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            textHour.setText(editHour.getText().toString());
            textTip.setText(editTip.getText().toString());
            wage = Float.parseFloat(textTip.getText().toString()) / Float.parseFloat(textHour.getText().toString());
            String tip = String.format("$%.2f",wage);
            textWage.setText(String.valueOf(tip) + " an hour");     
            textHour.setText(editHour.getText() + " Hour(s)");
            textTip.setText("$" + editTip.getText());
            bTip.putStringArray(sTip,new String[] {editTip.getText().toString()});
            bHour.putStringArray(sHour,new String[] {editHour.getText().toString()});
            tipList.addAll(Arrays.asList(sTip));
            hourList.addAll(Arrays.asList(sHour));
            i = new Intent(TipBookActivity.this,History.class);
            i.putExtras(bTip);
            i.putExtras(bHour);
        }       
    });
}
    public boolean onOptionsItemSelected(MenuItem item){
        switch (item.getItemId()){
        case R.id.menuHistory:
             startActivity(i));        // start Activity here by passing intent    
             return true;