Java 如何在登录成功时显示其他布局
我是Android新手，我有两个问题Java 如何在登录成功时显示其他布局,java,android,android-layout,Java,Android,Android Layout,我是Android新手，我有两个问题 我想在登录成功时显示另一个布局 else部分在onsuccess（）方法中不工作。如果用户提供了错误的用户名和密码，则表示抛出错误消息，但我收到错误： 应用程序不幸停止 这是我的密码： LoginFragment.java public void onSuccess(int statusCode, Header[] headers, byte[] response) { // Hide Progress Dialog
onsuccess（）方法中不工作。如果用户提供了错误的用户名和密码，则表示抛出错误消息，但我收到错误：
应用程序不幸停止
public void onSuccess(int statusCode, Header[] headers, byte[] response) {
// Hide Progress Dialog
prgDialog.hide();
try {
// JSON Object
JSONObject obj = new JSONObject(new String(response));
// When the JSON response has status boolean value assigned with true
if (obj.getBoolean("status")) {
Toast.makeText(getActivity().getApplicationContext(), "You are successfully logged in!", Toast.LENGTH_LONG).show();
// Navigate to Home screen
navigatetoSearchActivity();
}
// Else display error message
else {
errorMsg.setText(obj.getString("error_msg"));
Toast.makeText(getActivity().getApplicationContext(), obj.getString("error_msg"), Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
// TODO Auto-generated catch block
Toast.makeText(getActivity().getApplicationContext(), "Error Occured [Server's JSON response might be invalid]!", Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}
// When the response returned by REST has Http response code other than '200'
@Override
public void onFailure(int statusCode, Header[] headers, byte[] responsebody, Throwable error) {
// Hide Progress Dialog
prgDialog.hide();
// When Http response code is '404'
if (statusCode == 404) {
Toast.makeText(getActivity().getApplicationContext(), "Requested resource not found", Toast.LENGTH_LONG).show();
}
// When Http response code is '500'
else if (statusCode == 500) {
Toast.makeText(getActivity().getApplicationContext(), "Something went wrong at server end", Toast.LENGTH_LONG).show();
}
// When Http response code other than 404, 500
else {
Toast.makeText(getActivity().getApplicationContext(), "Unexpected Error occcured! [Most common Error: Device might not be connected to Internet or remote server is not up and running]", Toast.LENGTH_LONG).show();
}
}
});
}
/**
* Method which navigates from Login Activity to Search Activity
*/
public void navigatetoSearchActivity(){
Intent searchIntent = new Intent(getActivity().getApplicationContext(),Search.class);
//searchIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(searchIntent);
}
public void onSuccess(int statusCode, Header[] headers, byte[] response) {
// Hide Progress Dialog
prgDialog.hide();
try {
// JSON Object
JSONObject obj = new JSONObject(new String(response));
// When the JSON response has status boolean value assigned with true
if (obj.getBoolean("status")) {
Toast.makeText(getActivity().getApplicationContext(), "You are successfully logged in!", Toast.LENGTH_LONG).show();
// Navigate to Home screen
navigatetoSearchActivity();
}
// Else display error message
else {
errorMsg.setText(obj.getString("error_msg"));
Toast.makeText(getActivity().getApplicationContext(), obj.getString("error_msg"), Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
// TODO Auto-generated catch block
Toast.makeText(getActivity().getApplicationContext(), "Error Occured [Server's JSON response might be invalid]!", Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}
// When the response returned by REST has Http response code other than '200'
@Override
public void onFailure(int statusCode, Header[] headers, byte[] responsebody, Throwable error) {
// Hide Progress Dialog
prgDialog.hide();
// When Http response code is '404'
if (statusCode == 404) {
Toast.makeText(getActivity().getApplicationContext(), "Requested resource not found", Toast.LENGTH_LONG).show();
}
// When Http response code is '500'
else if (statusCode == 500) {
Toast.makeText(getActivity().getApplicationContext(), "Something went wrong at server end", Toast.LENGTH_LONG).show();
}
// When Http response code other than 404, 500
else {
Toast.makeText(getActivity().getApplicationContext(), "Unexpected Error occcured! [Most common Error: Device might not be connected to Internet or remote server is not up and running]", Toast.LENGTH_LONG).show();
}
}
});
}
/**
* Method which navigates from Login Activity to Search Activity
*/
public void navigatetoSearchActivity(){
Intent searchIntent = new Intent(getActivity().getApplicationContext(),Search.class);
//searchIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(searchIntent);
}
导入android.app.Activity；
导入android.os.Bundle；
公共类搜索扩展了活动{
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
//显示搜索屏幕
setContentView（R.layout.search）；
}
}
java.lang.RuntimeException: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.h2o/com.h2o.Search}; have you declared this activity in your AndroidManifest.xml?
at com.loopj.android.http.AsyncHttpResponseHandler.onUserException(AsyncHttpResponseHandler.java:313)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:404)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.h2o/com.h2o.Search}; have you declared this activity in your AndroidManifest.xml?
at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1761)
at android.app.Instrumentation.execStartActivity(Instrumentation.java:1485)
at android.app.Activity.startActivityForResult(Activity.java:3736)
at android.app.Activity.startActivityForResult(Activity.java:3697)
at android.support.v4.app.FragmentActivity.startActivityFromFragment(FragmentActivity.java:829)
at android.support.v4.app.Fragment.startActivity(Fragment.java:897)
at com.h2o.LoginFragment$TabsAdapter.navigatetoSearchActivity(LoginFragment.java:278)
at com.h2o.LoginFragment$TabsAdapter$3.onSuccess(LoginFragment.java:235)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:360)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
java.lang.RuntimeException: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.loopj.android.http.AsyncHttpResponseHandler.onUserException(AsyncHttpResponseHandler.java:313)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:404)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.h2o.LoginFragment$TabsAdapter$3.onSuccess(LoginFragment.java:239)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:360)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
java.lang.RuntimeException: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.h2o/com.h2o.Search}; have you declared this activity in your AndroidManifest.xml?
at com.loopj.android.http.AsyncHttpResponseHandler.onUserException(AsyncHttpResponseHandler.java:313)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:404)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.h2o/com.h2o.Search}; have you declared this activity in your AndroidManifest.xml?
at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1761)
at android.app.Instrumentation.execStartActivity(Instrumentation.java:1485)
at android.app.Activity.startActivityForResult(Activity.java:3736)
at android.app.Activity.startActivityForResult(Activity.java:3697)
at android.support.v4.app.FragmentActivity.startActivityFromFragment(FragmentActivity.java:829)
at android.support.v4.app.Fragment.startActivity(Fragment.java:897)
at com.h2o.LoginFragment$TabsAdapter.navigatetoSearchActivity(LoginFragment.java:278)
at com.h2o.LoginFragment$TabsAdapter$3.onSuccess(LoginFragment.java:235)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:360)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
java.lang.RuntimeException: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.loopj.android.http.AsyncHttpResponseHandler.onUserException(AsyncHttpResponseHandler.java:313)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:404)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.h2o.LoginFragment$TabsAdapter$3.onSuccess(LoginFragment.java:239)
at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:360)
at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:184)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
请在项目的清单文件中声明搜索类 样本：
<activity android:name=".Search"> </activity>
提供的日志中清楚地显示了错误。
1） 活动未在清单中声明。在活动标签中声明它。
2） 您在文本视图上设置文本而不初始化它。
例如：
TextView电视=（TextView）fingviewbyd（R.id.tv1）对于第一个问题，您似乎希望以新的布局开始新的活动。请阅读，这对主题非常有帮助（通过在IDE中添加活动，您不必自己编辑清单文件，其他答案会引导您）
对于第二个问题，您的errorMsg似乎未初始化。你需要带点东西
errorMsg = (TextView) findViewById(R.id.errorMessageId);
findViewById（）
是Activity
类的方法，所以对于第一个问题，您可能需要使用getActivity（）
获取它
在清单中添加搜索活动
的条目
<activity
android:name="com.packagename.yourMainActivityName" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
第二个问题：
检查以下几点可以解决您的问题：
1.检查您的响应是否为空
2.错误可能是从中获取状态的JSONobject
，请检查您的obj
是否为空
3.检查您是否已声明并初始化您的errorMsg
textview
你犯了什么错误？那不是错误。在这里复制你的日志。@Razul你考虑过给这个答案打分吗question@Appu也许考虑接受一个提供的答案？这是在这里说“谢谢”的方式：）