运行以下代码时出现异常。
public class LoginActivity extends Activity {
/** Called when the activity is first created. */
Button btnSend, btnDelete;
EditText edtUsername, edtPassword;
TextView tvUsername, tvPassword;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initializeProperties();
btnGonder.setOnClickListener(new OnClickListener() { public void onClick(View view) {
login("aaa@bbb.com", "123456");
}});
btnSil.setOnClickListener(new OnClickListener() { public void onClick(View view) {
clearView();
}});
}
private void initializeProperties() {
btnSend = (Button) findViewById(R.id.bSend);
btnDelete = (Button) findViewById(R.id.bDelete);
tvUsername = (TextView) findViewById(R.id.tvUsername);
edtUsername = (EditText) findViewById(R.id.etUsername);
tvPassword = (TextView) findViewById(R.id.tvPassword);
edtPassword = (EditText) findViewById(R.id.etPassword);
}
private static final String readInputStream(java.io.InputStream stream) throws IOException {
java.io.InputStreamReader streamReader = new java.io.InputStreamReader(stream);
java.io.BufferedReader bufferedReader = new java.io.BufferedReader(streamReader);
String line, redText = "";
while ((line = bufferedReader.readLine()) != null) {
redText += line;
}
bufferedReader.close();
return redText;
}
private void clearView() {
edtPassword.setText("");
}
private void login(String username, String password) {
HttpPost httpPost = new HttpPost("http://192.168.1.1/api/login");
AlertDialog.Builder alertBuilder = new AlertDialog.Builder(getApplicationContext());
alertBuilder.setCancelable(true);
//HttpResponse response = null;
try {
// Add your data
httpPost.setEntity(new StringEntity(
String.format("{ 'Email': '%s', 'Password': '%s' }", username, password)
));
// Set Headers
httpPost.setHeader("Content-Type", "application/json; charset=utf-8");
// Execute HTTP Post Request
//response = new AsyncLoginHandler(alertBuilder).execute(httpPost).get();
new AsyncLoginHandler(alertBuilder).execute(httpPost);
} catch (UnsupportedEncodingException uee) {
alertBuilder.setMessage(uee.getMessage());
}
}
class AsyncLoginHandler extends android.os.AsyncTask<HttpPost, Void, HttpResponse> {
AlertDialog.Builder alertBuilder;
AsyncLoginHandler(AlertDialog.Builder alertBuilder) {
super();
this.alertBuilder = alertBuilder;
}
@Override
protected HttpResponse doInBackground(HttpPost... params) {
HttpClient httpClient = new DefaultHttpClient();
HttpResponse httpResponse = null;
for (int i = 0; i < params.length; i++) {
try {
httpResponse = httpClient.execute(params[i]);
} catch (ClientProtocolException cpe) {
alertBuilder.setMessage(cpe.getMessage());
} catch (IOException ioe) {
alertBuilder.setMessage(ioe.getMessage());
} catch (Exception e) {
alertBuilder.setMessage(e.getMessage());
}
}
return httpResponse;
}
@Override
protected void onPostExecute(HttpResponse response) {
if (response != null) {
try {
java.io.InputStream stream = response.getEntity().getContent();
String result = readInputStream(stream);
alertBuilder.setMessage(result);
} catch (IllegalStateException ise) {
alertBuilder.setMessage(ise.getMessage());
} catch (IOException ioe) {
alertBuilder.setMessage(ioe.getMessage());
}
}
super.onPostExecute(response);
alertBuilder.create().show();
}
}
}
嗯...... Android AsyncTask的文档页面（请参阅标题“4步骤”）指出在UI线程上调用了onPostExecute;但是在“ alertBuilder.create（）。show（）;”之后我遇到以下错误。
- 10-04 06:36:25.607: W/dalvikvm(711): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
- 10-04 06:36:25.657: E/AndroidRuntime(711): FATAL EXCEPTION: main
- 10-04 06:36:25.657: E/AndroidRuntime(711): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.view.ViewRootImpl.setView(ViewRootImpl.java:517)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:301)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.app.Dialog.show(Dialog.java:278)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at org.gdgankara.com.LoginActivity$AsyncLoginHandler.onPostExecute(LoginActivity.java:139)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at org.gdgankara.com.LoginActivity$AsyncLoginHandler.onPostExecute(LoginActivity.java:1)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.os.AsyncTask.finish(AsyncTask.java:602)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.os.AsyncTask.access$600(AsyncTask.java:156)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:615)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.os.Handler.dispatchMessage(Handler.java:99)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.os.Looper.loop(Looper.java:137)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at android.app.ActivityThread.main(ActivityThread.java:4424)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at java.lang.reflect.Method.invokeNative(Native Method)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at java.lang.reflect.Method.invoke(Method.java:511)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
- 10-04 06:36:25.657: E/AndroidRuntime(711): at dalvik.system.NativeStart.main(Native Method)
有人可以帮忙吗？
答案 0 :(得分：-1)
doInBackground方法无法触及主线程的视图。这意味着您无法通过doInBackground方法设置警报对话框的消息。尝试从doInBackground中的catch中删除set 3 set消息并运行应用程序。