Question

我有两项活动。当用户点击列表上的药品名称时，它将转到第二个活动并显示药品的详细信息。对于第一项活动，以下是我的代码：

public class MedicineView extends Activity implements AdapterView.OnItemClickListener
{
private SQLiteDatabase database;
private ArrayList<String> result = new ArrayList<String>(); 
private ArrayList<Long> idList = new ArrayList<Long>();
private ArrayAdapter<String> adapter;

@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.medicine_view);
    ListView listContent = (ListView)findViewById(R.id.listView1);

    DBHelper helper = new DBHelper(this);
    database = helper.getWritableDatabase();

    // view data

    try{
        String query = "select * from " + DBHelper.TABLE_MEDICINE;

        Cursor c = database.rawQuery(query, null);

        if(c!=null)
        {
            c.moveToFirst();
            int getIndex = c.getColumnIndex(DBHelper.MED_ID);
            int getNameIndex = c.getColumnIndex(DBHelper.MED_NAME);
            int getDosageIndex = c.getColumnIndex(DBHelper.DOSAGE);
            int getFrequencyIndex = c.getColumnIndex(DBHelper.FREQUENCY);

            if(c.isFirst())
            {
                do{
                    idList.add(c.getLong(getIndex));
                    result.add(c.getString(getNameIndex)+" | " + c.getString(getDosageIndex)
                            +" | " + c.getString(getFrequencyIndex)+"\n" );
                }while(c.moveToNext());
            }
        }

        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,result);
        listContent.setAdapter(adapter);
        listContent.setTextFilterEnabled(true);

        c.close();

    }
    catch(SQLException e){  
    }

    listContent.setOnItemClickListener(this);
}

public void onClickHome(View v){
    startActivity (new Intent(getApplicationContext(), MenuUtama.class));
}

public void onClickAdd(View v){
    startActivity (new Intent(getApplicationContext(), MedicineAdd.class));
}

@Override
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
    Intent myIntent = new Intent(v.getContext(), MedicineDetail.class);
    myIntent.putExtra("ID", id);
    startActivity(myIntent);
}
} // end class

这是我的第二项活动

public class MedicineDetail extends Activity 
 {
private SQLiteDatabase database;
private ArrayList<Long> idList = new ArrayList<Long>();
ArrayList<String> list = new ArrayList<String>();

Button btnEdit;

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

    Intent i = getIntent();
    final int id = i.getIntExtra("int", -1);
    //int id = getIntent().getIntExtra("id", 2);

    btnEdit = (Button)findViewById(R.id.imageButton2);

    DBHelper helper = new DBHelper(this);
    database = helper.getWritableDatabase();

    String sql = "select * from " + DBHelper.TABLE_MEDICINE + " WHERE id = " + id;
    Cursor cursor = database.rawQuery(sql, null);

    try{
        if( cursor != null ){
            if (cursor.moveToFirst()) {
               do {
                   idList.add(cursor.getLong(0));
                   list.add(cursor.getString(1));
                   list.add(cursor.getString(2));
                   list.add(cursor.getString(3));
                   list.add(cursor.getString(4));
                   list.add(cursor.getString(5));
                   list.add(cursor.getString(6));
               } while (cursor.moveToNext());
            }
        }
    }
    catch(SQLException e){  
    }

    cursor.moveToFirst();

    TextView StartDate = (TextView) findViewById(R.id.textView8);
    TextView EndDate = (TextView)findViewById(R.id.textView9);
    TextView MedName = (TextView)findViewById(R.id.textView10);
    TextView Dosage = (TextView)findViewById(R.id.textView11);
    TextView Frequency =    (TextView)findViewById(R.id.textView12);
    TextView Instruction =  (TextView)findViewById(R.id.textView13);

    StartDate.setText(cursor.getString(1));
    EndDate.setText(cursor.getString(2));
    MedName.setText(cursor.getString(3));
    Dosage.setText(cursor.getString(4));
    Frequency.setText(cursor.getString(5));
    Instruction.setText(cursor.getString(6));
    cursor.close();

}

public void onClickHome(View v){
    startActivity (new Intent(getApplicationContext(), MedicineView.class));
}

} // end class

这是我的logcat

03-05 08:55:08.985: W/Bundle(2186): Key ID expected Integer but value was a    java.lang.Long.  The default value -1 was returned.
03-05 08:55:09.005: W/Bundle(2186): Attempt to cast generated internal exception:
03-05 08:55:09.005: W/Bundle(2186): java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer
03-05 08:55:09.005: W/Bundle(2186):     at android.os.Bundle.getInt(Bundle.java:933)
03-05 08:55:09.005: W/Bundle(2186):     at android.content.Intent.getIntExtra(Intent.java:3683)
03-05 08:55:09.005: W/Bundle(2186):     at com.android.MyDoc.MedicineDetail.onCreate(MedicineDetail.java:32)
03-05 08:55:09.005: W/Bundle(2186):     at android.app.Activity.performCreate(Activity.java:4465)
03-05 08:55:09.005: W/Bundle(2186):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-05 08:55:09.005: W/Bundle(2186):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
03-05 08:55:09.005: W/Bundle(2186):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
03-05 08:55:09.005: W/Bundle(2186):     at android.app.ActivityThread.access$600(ActivityThread.java:122)
03-05 08:55:09.005: W/Bundle(2186):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
03-05 08:55:09.005: W/Bundle(2186):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-05 08:55:09.005: W/Bundle(2186):     at android.os.Looper.loop(Looper.java:137)
03-05 08:55:09.005: W/Bundle(2186):     at android.app.ActivityThread.main(ActivityThread.java:4340)
03-05 08:55:09.005: W/Bundle(2186):     at java.lang.reflect.Method.invokeNative(Native Method)
03-05 08:55:09.005: W/Bundle(2186):     at  java.lang.reflect.Method.invoke(Method.java:511)
03-05 08:55:09.005: W/Bundle(2186):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-05 08:55:09.005: W/Bundle(2186):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-05 08:55:09.005: W/Bundle(2186):     at dalvik.system.NativeStart.main(Native Method)
03-05 08:55:09.053: D/AndroidRuntime(2186): Shutting down VM
03-05 08:55:09.053: W/dalvikvm(2186): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
03-05 08:55:09.093: E/AndroidRuntime(2186): FATAL EXCEPTION: main
03-05 08:55:09.093: E/AndroidRuntime(2186): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.MyDoc/com.android.MyDoc.MedicineDetail}: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1955)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.ActivityThread.access$600(ActivityThread.java:122)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.os.Looper.loop(Looper.java:137)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.ActivityThread.main(ActivityThread.java:4340)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at java.lang.reflect.Method.invokeNative(Native Method)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at java.lang.reflect.Method.invoke(Method.java:511)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at dalvik.system.NativeStart.main(Native Method)
03-05 08:55:09.093: E/AndroidRuntime(2186): Caused by: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.database.AbstractCursor.checkPosition(AbstractCursor.java:434)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at com.android.MyDoc.MedicineDetail.onCreate(MedicineDetail.java:70)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.Activity.performCreate(Activity.java:4465)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-05 08:55:09.093: E/AndroidRuntime(2186):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
03-05 08:55:09.093: E/AndroidRuntime(2186):     ... 11 more

Answer 1

在第二个活动中存在问题

in the first activity 



 Intent myIntent = new Intent(v.getContext(), MedicineDetail.class);
    myIntent.putExtra("ID", position);
    startActivity(myIntent);



final int id = i.getIntExtra("int", -1); should be

final int id = i.getIntExtra("ID", -1);

Answer 2

在您的来电活动中：myIntent.putExtra("ID", id);

在打开的活动中而不是

i.getIntExtra("int", -1);

应该是

i.getIntExtra("ID", -1);

请注意，当您尝试从意图中获取额外名称时，该名称应该相同。

Answer 3

第一次行动中的

将id更改为position。就是这样。

 myIntent.putExtra("ID", position);

和第二次

getIntExtra("ID", -1);

或

getExtra("ID", -1);

Answer 4

编辑：你得到的是long值，但是id返回int，所以它抛出了classcast异常

而不是

idList.add(cursor.getLong(0));

使用此

 idList.add(cursor.getInt(0));

你的id与表格中的rowid不同。不要搞砸他们，你发送列表中的位置的id。所以你需要做的是

创建一个Hashmap以使用全局数据映射ID

Hashmap Idshash=new Hashmap();

插入结果列表时向hasmap添加值

long id=c.getLong(getIndex);
String item=c.getString(getNameIndex)+" | " + c.getString(getDosageIndex)
                            +" | " + c.getString(getFrequencyIndex);
   idList.add(id);
Idshash.put(item,id);
  result.add(item);

在onitemclick听众中喜欢这个

@Override
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
    String item=((TextView)v).getText();
    long selectedid=Idshash.get(item);
    Intent myIntent = new Intent(v.getContext(), MedicineDetail.class);
    myIntent.putExtra("ID", selectedid);
    startActivity(myIntent);
}

将列表的行ID传递给另一个活动

4 个答案: