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你好我新在stackover流我想尝试这些网站，并要求在我的机器人someones帮助，当我改变意图有一个错误在android工作室显示器在android工作室这里是它。Android意图错误null对象引用
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.kim.checkerv3, PID: 2970
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.kim.checkerv3/com.example.kim.checkerv3.BudgetOutput}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.os.BaseBundle.getString(java.lang.String)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.os.BaseBundle.getString(java.lang.String)' on a null object reference
at com.example.kim.checkerv3.BudgetOutput.onCreate(BudgetOutput.java:22)
at android.app.Activity.performCreate(Activity.java:6664)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
我不明白这个我试图研究解决方案，我仍然坚持下去。
这里的意图将传递给其他java类。
package com.example.kim.checkerv3;
import android.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AlertDialog;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import static android.content.Context.MODE_PRIVATE;
/**
* Created by KIM-PC on 12/5/2016.
*/
public class BudgetFragment extends android.support.v4.app.Fragment {
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_budget, container, false);
final EditText etCash = (EditText) v.findViewById(R.id.etCash);
final Button bBudget = (Button) v.findViewById(R.id.bBudget);
bBudget.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
SharedPreferences sharedpref = getContext().getSharedPreferences("user_id", MODE_PRIVATE);
String id = sharedpref.getString("user_id","");
final int budgeted = Integer.parseInt(etCash.getText().toString());
Response.Listener<String> responseListener = new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject jsonResponse = new JSONObject(response);
JSONArray arr = jsonResponse.getJSONArray("message");
boolean success = jsonResponse.getBoolean("success");
System.out.println(budgeted/arr.length());
int total = budgeted/arr.length();
if (success) {
Intent intent = new Intent(getContext(), BudgetOutput.class);
Bundle b = new Bundle();
b.putString("total", String.valueOf(total));
getContext().startActivity(intent);
if (arr != null) {
int sum = 0;
for(int i = 0;i<arr.length();i++){
//listdata.add(arr.get(i).toString());
String money = arr.getJSONObject(i).getString("amount");
sum += Integer.parseInt(money);
}
SharedPreferences sharedPref1 = getActivity().getSharedPreferences("mypref", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref1.edit();
editor.putInt("TotalSum", sum);
editor.commit();
System.out.println(sum);
//arrayAdapter.notifyDataSetChanged();
}
} else {
AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
builder.setMessage("Failed to fetch. Try again.")
.setNegativeButton("OK", null)
.create()
.show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
};
RecordRequest recordRequest = new RecordRequest(id, responseListener);
RequestQueue queue = Volley.newRequestQueue(getContext());
queue.add(recordRequest);
}
});
return v;
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
SharedPreferences sharedpref1 = getContext().getSharedPreferences("mypref", MODE_PRIVATE);
int budgeted = sharedpref1.getInt("TotalSum", 0);
System.out.println(budgeted/2);
}
}
和意图得到的类。
package com.example.kim.checkerv3;
import android.content.Intent;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.EditText;
import android.widget.TextView;
/**
* Created by KIM-PC on 12/6/2016.
*/
public class BudgetOutput extends AppCompatActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_output);
final TextView tvOutput = (TextView) findViewById(R.id.tvoutput);
Bundle b = getIntent().getExtras();
String output=b.getString("total");
if(b !=null)
output = b.getString("total");
tvOutput.setText(output+" Per cheque record.");
}
}
如果有人能解决我欣赏并向我致谢。