我需要在一个数据库中使用两个表填充自定义ListView。
为什么有两张桌子？
我在两个表中都有一些数据，我可以在它们的onStart aplication上插入新项目。第一个表有一些动物名称，第二个表有一些植物名称。
FirstTable
动物
猫
狗
猪
SecondTable
植物：
玫瑰
兰
三叶草
我需要在同一个自定义ListView中显示两个表的项目。
生活世界ListView 猫
狗
猪
玫瑰
兰
三叶草
如果我将一个项目添加到两个表中的任何一个，它应该显示在自定义ListView
上猫
狗
猪
兔
玫瑰
兰
三叶草
我试过了。但它不起作用：
CODE：
MainActivity.java
public class MainActivity extends ListActivity {
public sql myDbHelper, myDbHelper2;
public SQLiteDatabase db = null, db2=null;
public List<String> show, show2, show3, show4;
AdaptadorTitulares adapter;
public ListView list;
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
// if extending Activity
setContentView(R.layout.activity_main);
try {
myDbHelper = new sql(this);
myDbHelper.createDataBase(this);
} catch (Exception e) {
}
new threadbd().execute();
list = (ListView) findViewById(android.R.id.list);
list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int posicion, long arg3) {
//........
}
});
}
//..............
//NOT IMPORTANT CODE
//..............
private class threadbd extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) {
myDbHelper.openDataBase();
myDbHelper2.openDataBase();
db = myDbHelper.getReadableDatabase();
db2 = myDbHelper2.getReadableDatabase();
Cursor c = db.rawQuery("SELECT id FROM animal order by id desc",
null);
c.moveToFirst();
int num = c.getInt(0);
Cursor e = db2.rawQuery("SELECT id FROM plants order by id desc",
null);
e.moveToFirst();
int num2 = e.getInt(0);
// creo array
show = new ArrayList<String>(num);
show2 = new ArrayList<String>(num);
show3 = new ArrayList<String>(num2);
show4 = new ArrayList<String>(num2);
for (int i = 0; i <= num; i++) {
Cursor d = db.rawQuery(
"SELECT name, group FROM animal WHERE id=" + i + "",
null);
if (d.moveToFirst()) {
show.add(d.getString(0));
show2.add(String.valueOf(d.getDouble(1)));
}
for (int j = 0; j <= num2; j++) {
Cursor f = db2.rawQuery(
"SELECT name, group FROM comida WHERE id=" + j + "",
null);
if (f.moveToFirst()) {
show3.add(f.getString(0));
show4.add(String.valueOf(f.getDouble(1)));
}
}// end for
}
return null;
}// end InBackground
protected void onPostExecute(Void result) {
Titular titular, titular2;
ArrayList<Titular> mList = new ArrayList<Titular>();
for (int i = 0; i < show.size(); i++) {
try {
titular = new Titular(show.get(i), show2.get(i));
titular2 = new Titular(show.get(i), show.get(i));
mList.add(titular);
mList.add(titular2);
} catch (Exception e) {
}
AdaptadorTitulares actualizaAdapter=new AdaptadorTitulares(MainActivity.this, mList);
list.setAdapter(actualizaAdapter);
}
}
}
}
Titular.java
public class Titular {
private String group;
private String title;
public Titular(String group, String title) {
this.group = group;
this.title = title;
}
public String getGroup() {
return group;
}
public void setGroup(String group) {
this.group = group;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
}
表1
ID 名称 组
表2
ID 名称 组
由于
更新
06-08 16:47:35.802: E/AndroidRuntime(1242): FATAL EXCEPTION: AsyncTask #1
06-08 16:47:35.802: E/AndroidRuntime(1242): Process: com.example.listprueba, PID: 1242
06-08 16:47:35.802: E/AndroidRuntime(1242): java.lang.RuntimeException: An error occured while executing doInBackground()
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.os.AsyncTask$3.done(AsyncTask.java:300)
06-08 16:47:35.802: E/AndroidRuntime(1242): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
06-08 16:47:35.802: E/AndroidRuntime(1242): at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
06-08 16:47:35.802: E/AndroidRuntime(1242): at java.util.concurrent.FutureTask.run(FutureTask.java:242)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
06-08 16:47:35.802: E/AndroidRuntime(1242): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
06-08 16:47:35.802: E/AndroidRuntime(1242): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
06-08 16:47:35.802: E/AndroidRuntime(1242): at java.lang.Thread.run(Thread.java:841)
06-08 16:47:35.802: E/AndroidRuntime(1242): Caused by: android.database.sqlite.SQLiteException: near "ALLSELECT": syntax error (code 1): , while compiling: SELECT _id + 1000000, nombre, precio FROM bebida UNION ALLSELECT _id + 2000000, nombre, precio FROM comida
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253)
06-08 16:47:35.802: E/AndroidRuntime(1242): at com.example.listprueba.MainActivity$threadbd.doInBackground(MainActivity.java:216)
06-08 16:47:35.802: E/AndroidRuntime(1242): at com.example.listprueba.MainActivity$threadbd.doInBackground(MainActivity.java:1)
06-08 16:47:35.802: E/AndroidRuntime(1242): at android.os.AsyncTask$2.call(AsyncTask.java:288)
06-08 16:47:35.802: E/AndroidRuntime(1242): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
06-08 16:47:35.802: E/AndroidRuntime(1242): ... 4 more
06-08 16:47:35.902: W/EGL_genymotion(1242): eglSurfaceAttrib not implemented
06-08 16:47:35.902: E/OpenGLRenderer(1242): Getting MAX_TEXTURE_SIZE from GradienCache
06-08 16:47:35.902: E/OpenGLRenderer(1242): MAX_TEXTURE_SIZE: 8192
06-08 16:47:35.922: E/OpenGLRenderer(1242): Getting MAX_TEXTURE_SIZE from Caches::initConstraints()
06-08 16:47:35.922: E/OpenGLRenderer(1242): MAX_TEXTURE_SIZE: 8192
答案 0 :(得分：2)
使用像这样的compound query来获得单个结果集：
SELECT _id + 1000000, name, "group" FROM animal
UNION ALL
SELECT _id + 2000000, name, "group" FROM comida
（添加的数字使ID唯一。）
这允许您以通常的方式使用简单的cursor adapter在列表视图中自动显示此数据。