此方法是获取包含三个EditText框和一个由string-array填充的微调器的输入。单击该按钮是进行计算的触发器。按下OnClick方法时，应用程序崩溃。代码如下
package biz.avksons.siddharth.hydro_basic_calc;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
public class UoE extends AppCompatActivity {
// Define variables for Spinner here
Spinner spinner_1;
String spin_select;
boolean dbug=true;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_uoe);
}
// ************************************************************************************
// Start the method to calculate the units of electricity here
public void onUoECalc_ButtonClick(View v) {
/* Define Custom method for calculating the Units of electricity on clicking the Calculate button*/
//Processing variable for count
boolean flag = false; // Used to check if the inputs done in the EditText are valid or not, else there will an exception which would lead to application crash
/* Initiate the Variables here*/
//-----------------------------------------------------
//Allocate the ids of EditText to the variables for further use
EditText et_capacity = (EditText) findViewById(R.id.et_uoe_capacity);
EditText et_plf = (EditText) findViewById(R.id.et_uoe_plf);
EditText et_availability = (EditText) findViewById(R.id.et_uoe_availability);
EditText et_energy = (EditText) findViewById(R.id.et_uoe_mus);
//Variable for deciding Timeperiod
Double time_period = 365.00;
//---DEBUG <code></code>
if (dbug)
{
Toast.makeText(this, "Spiner selection : " + spin_select, Toast.LENGTH_SHORT).show();
}
//Set flag to true only if the inputs in the two edittext, discharge and head are sensible inputs
if (checkedittext(et_capacity) && checkedittext(et_plf) && checkedittext(et_availability)) {
flag = true;
} else {
//If the inputs in discharge are not sensible then display the message to input a sensible input before moving further
Toast.makeText(this, "Please enter valid inputs", Toast.LENGTH_LONG).show();
// Set the EditText box of the output to blank if the inputs are not valid as tested in the above statements
et_capacity.setText("");
}
// do this operation only if the flag is set to true which are tested above
if (flag == true) {
//-------Initiating Spinner here
addListenerOnSpinnerItemSelection();
// Set selection default for Spinner here
// spinner_1.setSelection(1);
//--------Allocation of Spin Button Here-------------
if (dbug)
{
Toast.makeText(this, "Spin_select"+ spin_select, Toast.LENGTH_SHORT).show();
}
switch (spin_select) {
case "1 yr":
time_period = 365.00;
case "6 mon":
time_period = 180.00;
case "3 mon":
time_period = 90.00;
}
//-------End of Spin Button--------------
//Assign the values here
Double d_capacity = Double.parseDouble(et_capacity.getText().toString());
Double d_plf = Double.parseDouble(et_plf.getText().toString());
Double d_availability = Double.parseDouble(et_availability.getText().toString());
//-DEBUG Code----
if(dbug)
{
Toast.makeText(this, "Time Period selected" + time_period.toString(), Toast.LENGTH_SHORT).show();
}
Double d_energy = Double.valueOf((d_capacity * 1000 * 24 * time_period * d_plf * d_availability) / 1000000);
et_energy.setText(Double.toString(Math.round(d_energy))); // In MW
// capacity.setText(String.format(".2%f",Double.toString(C)));
}
}
//Method to check for validity of contents in edittext
public boolean checkedittext(EditText edtxt) {
if (edtxt.getText().toString().matches("")) {
return false;
} else {
return true;
}
}
//--------Method to get the selected option from Spinner
public void addListenerOnSpinnerItemSelection() {
//------Declare a variable on Spinner and allocate the id here
spinner_1 = (Spinner) findViewById(R.id.spin_uoe_period);
spinner_1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
{
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
{
spin_select = parent.getItemAtPosition(position).toString();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
public void onHelp_UoE(View v)
{
Toast.makeText(this,"Please enter valid figures in the boxes mentioned and select the period you are interested in; from the dropdown menu before pressing calculate",Toast.LENGTH_LONG).show();
}
}
Logcat中的错误如下
E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:4240)
at android.view.View$PerformClick.run(View.java:17721)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4240)
at android.view.View$PerformClick.run(View.java:17721)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at biz.avksons.siddharth.hydro_basic_calc.UoE.onUoECalc_ButtonClick(UoE.java:84)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4240)
at android.view.View$PerformClick.run(View.java:17721)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
我试图找到NullPointerException错误，根据代码表明spinner_select变量未初始化。我的理解告诉我，每次调用方法时都应该初始化spinner_select变量。
请求帮助。谢谢你
答案 0 :(得分：0)
我希望你错过了
break;
在switch case statement
中