为什么它没有获取任何数据？

huangapple
go评论145阅读模式
英文:

Why doesn't it get any data?

问题

Main:

  1.     ColegiListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
  2.         @Override
  3.         public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
  4.             Intent intent = new Intent(MainActivity.this, ColegDataEditActivity.class);
  5.             intent.putExtra("Id", Integer.parseInt(Long.toString(id)));
  6.             Log.i("Id", id + "");
  7.             startActivity(intent, ActivityOptions.makeSceneTransitionAnimation(MainActivity.this).toBundle());
  8.         }
  9.     });

DATABASE HELPER:

  1.     public Cursor getSpecificData(int id) {
  2.         SQLiteDatabase db = this.getWritableDatabase();
  3.         Cursor data = db.rawQuery("SELECT * FROM " + TableName + " WHERE ID =" + id, null);
  4.         return data;
  5.     }

SECOND ACTIVITY:

  1.     Intent intent = getIntent();
  2.     int id = intent.getIntExtra("Id", 0);
  3.     Cursor data = mDatabase.getSpecificData(id);

Hi! I am a beginner with SQL and I don't know what I did wrong. I have a database with multiple columns and I need to get some data from it so then I can put those values in some TextViews. The problem is that the data I need needs to be a single row with the specific id from an item from a ListView (yeah, I know about row id, I solved that problem). Any ideas why isn't it working?

英文:

Main:

  1. ColegiListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
  2.             @Override
  3.             public void onItemClick(AdapterView&lt;?&gt; parent, View view, int position, long id) {
  4.                 Intent intent = new Intent(MainActivity.this, ColegDataEditActivity.class);
  5.                 intent.putExtra(&quot;Id&quot;, Integer.parseInt(Long.toString(id)));
  6.                 Log.i(&quot;Id&quot;,id+&quot;&quot;);
  7.                 startActivity(intent, ActivityOptions.makeSceneTransitionAnimation(MainActivity.this).toBundle());
  8.             }
  9.         });

DATABASE HELPER:

  1. public Cursor getSpecificData(int id){
  2.     SQLiteDatabase db = this. getWritableDatabase();
  3.     Cursor data = db.rawQuery(&quot;SELECT * FROM &quot;+ TableName + &quot; WHERE ID =&quot;+id, null);
  4.     return data;
  5. }

SECOND ACTIVITY:

  1. Intent intent = getIntent();
  2.     int id =intent.getIntExtra(&quot;Id&quot;,0);
  3.         Cursor data = mDatabase.getSpecificData(id);

Hi! I am a beginner with SQL and I don't know what I did wrong. I have a database with multiple columns and I need to get some data from it so then I can put those values in some TextViews. The problem is that the data I need needs to be a single row with the specific id from an item from a ListView (yeah, I now about row id, I solved that problem). Any ideas why isn't it working?

答案1

得分: 1

Your Database Helper

  1. public Cursor getSpecificData(int id){
  2.     SQLiteDatabase db = this.getWritableDatabase();
  3.     String query = "SELECT * FROM " + TableName + " WHERE ID = " + id;
  4.     Cursor res = db.rawQuery(query, null);
  5.     return res;
  6. }

In Activity make a setViews function

  1. public void setViews() {
  2.     Cursor cursor = mDatabase.getSpecificData(id);
  3.     try {
  4.         if (cursor.getCount() != 0) {
  5.             if (cursor.moveToFirst()) {
  6.                 textview1.setText(cursor.getString(cursor.getColumnIndex(DatabaseHelper.COLUMN_1_NAME)));
  7.                 textview2.setText(cursor.getString(cursor.getColumnIndex(DatabaseHelper.COLUMN_2_NAME)));
  8.                 //and so on
  9.             }
  10.         }
  11.     } finally {
  12.         if (cursor != null) {
  13.             cursor.close();
  14.         }
  15.     }
  16. }
英文:

Your Database Helper

  1. public Cursor getSpecificData(int id){
  2.     SQLiteDatabase db = this.getWritableDatabase();
  3.     String query = &quot;SELECT * FROM &quot;+ TableName + &quot; WHERE ID = &quot;+id;
  4.     Cursor res = db.rawQuery(query, null);
  5.     return res;
  6. }

In Activity make a setViewsfunction

  1. public void setViews() {
  2.             Cursor cursor = mDatabase.getSpecificData(id);
  3.             try {
  4.                 if (cursor.getCount() != 0) {
  5.                     if (cursor.moveToFirst()) {
  6.                         textview1.setText(cursor.getString(cursor.getColumnIndex(DatabaseHelper.COLUMN_1_NAME)));
  7.                         textview2.setText(cursor.getString(cursor.getColumnIndex(DatabaseHelper.COLUMN_2_NAME)));
  8.                         //and so on
  9.     
  10.                     }
  11.     
  12.                 }
  13.             } finally {
  14.                 if (cursor != null) {
  15.                     cursor.close();
  16.                 }
  17.             }
  18.         }

huangapple
  • 本文由 发表于 2020年4月10日 22:39:34
  • 转载请务必保留本文链接：https://go.coder-hub.com/61142618.html
  • android
  • java
  • sql
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