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我觉得这种问题有点愚蠢，因为我有另一个应用程序，它可以正常工作，或者至少我认为它是相同的。我对此肯定需要另一套眼睛，因为对我来说，它看起来应该起作用。我的代码如下：Android Handler无法访问图形用户界面元素
public class InventorySystemActivity extends Activity {
private EditText barcode;
private EditText proddesc;
private EditText quantity;
public String scan_result;
public int which;
private InventorySystemDB db;
public Item singleItem;
public Item[] itemList;
private Thread t;
Handler handler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 1:
barcode.setText(scan_result);
proddesc.setText(singleItem.name);
quantity.setText(singleItem.quantity);
break;
case 3:
updateUI();
pd.dismiss();
}
}
};
public static Intent in = new Intent("com.google.zxing.client.android.SCAN");
private ProgressDialog pd;
private Thread dbt;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.db = new InventorySystemDB(this);
try {
this.db.createDataBase();
this.db.openDataBase();
} catch (Exception e) {
e.printStackTrace();
}
this.dbt = new Thread(this.db);
setContentView(R.layout.main);
Button scan = (Button) findViewById(R.id.scan);
scan.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
startActivityForResult(in, 0);
}
});
Button search = (Button) findViewById(R.id.searchbutton);
search.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
pd.show();
which = 1;
scan_result = barcode.getText().toString();
dbt.start();
}
});
barcode = (EditText) findViewById(R.id.barcodenum);
proddesc = (EditText) findViewById(R.id.proddesc);
quantity = (EditText) findViewById(R.id.prodquantity);
pd = new ProgressDialog(this);
pd.setMessage("Loading data...");
}
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (requestCode == 0) {
if (resultCode == RESULT_OK) {
scan_result = intent.getStringExtra("SCAN_RESULT");
barcode.setText(scan_result);
} else if (resultCode == RESULT_CANCELED) {
}
}
}
private void updateUI() {
barcode.setText(singleItem.upc);
proddesc.setText(singleItem.name);
quantity.setText("0");
}
}
我所有的线程做是需要的UPC号码，并从一对夫妇的网站拉信息。代码发送消息到处理程序很好，我已经使用线程和处理程序创建了一些类似的应用程序，但不知道为什么现在有这个问题。无论如何，我可以关闭ProgressDialog，但我无法更新任何UI对象。这一切对我来说都很好，所以我真的需要更多的眼光。多谢你们。