我正在做一个涉及计算的Android应用程序。 现在，我正在做第一部分，尝试登录。 我创建了一个数据库，用于存储用户注册的信息，这样当用户注册时，信息将存储在数据库中，然后将用于登录。
登录后，它会显示另一个页面，即activity_main.xml 但是，当我尝试登录时，会出现强制关闭错误。
以前，当我尝试时，没有错误，我可以成功登录。 但是，在我添加MainActivity.java中的代码并尝试登录后， 错误开始发生。
有人能帮助我吗？ 我是处理日食的新手。
这是我的logcat错误
01-20 05:02:44.773: E/AndroidRuntime(1159): FATAL EXCEPTION: main
01-20 05:02:44.773: E/AndroidRuntime(1159): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fuellog/com.example.fuellog.MainActivity}: java.lang.NumberFormatException: Invalid float: "floatvalue"
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.os.Handler.dispatchMessage(Handler.java:99)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.os.Looper.loop(Looper.java:137)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.ActivityThread.main(ActivityThread.java:5041)
01-20 05:02:44.773: E/AndroidRuntime(1159): at java.lang.reflect.Method.invokeNative(Native Method)
01-20 05:02:44.773: E/AndroidRuntime(1159): at java.lang.reflect.Method.invoke(Method.java:511)
01-20 05:02:44.773: E/AndroidRuntime(1159): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-20 05:02:44.773: E/AndroidRuntime(1159): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-20 05:02:44.773: E/AndroidRuntime(1159): at dalvik.system.NativeStart.main(Native Method)
01-20 05:02:44.773: E/AndroidRuntime(1159): Caused by: java.lang.NumberFormatException: Invalid float: "floatvalue"
01-20 05:02:44.773: E/AndroidRuntime(1159): at java.lang.StringToReal.invalidReal(StringToReal.java:63)
01-20 05:02:44.773: E/AndroidRuntime(1159): at java.lang.StringToReal.initialParse(StringToReal.java:94)
01-20 05:02:44.773: E/AndroidRuntime(1159): at java.lang.StringToReal.parseFloat(StringToReal.java:304)
01-20 05:02:44.773: E/AndroidRuntime(1159): at java.lang.Float.parseFloat(Float.java:300)
01-20 05:02:44.773: E/AndroidRuntime(1159): at com.example.fuellog.MainActivity.onCreate(MainActivity.java:39)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.Activity.performCreate(Activity.java:5104)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-20 05:02:44.773: E/AndroidRuntime(1159): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-20 05:02:44.773: E/AndroidRuntime(1159): ... 11 more
这是homeactivity.java的代码
public class homeActivity extends Activity{
Button btnSignIn,btnSignUp;
Button btnAbout;
LoginDataBaseAdapter loginDataBaseAdapter;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.homescreen);
// create a instance of SQLite Database
loginDataBaseAdapter=new LoginDataBaseAdapter(this);
loginDataBaseAdapter=loginDataBaseAdapter.open();
// Get The Reference Of Buttons
btnSignIn=(Button)findViewById(R.id.buttonSignIN);
btnSignUp=(Button)findViewById(R.id.buttonSignUP);
btnAbout=(Button)findViewById(R.id.aboutBTN);
// Set OnClick Listener on SignUp button
btnSignUp.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
/// Create Intent for SignUpActivity abd Start The Activity
Intent intentSignUP=new Intent(getApplicationContext(),SignUpActivity.class);
startActivity(intentSignUP);
}
});
// set OnClick Listener on About button
btnAbout.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
/// Create Intent for About and start activity
Intent intentAbout=new Intent(getApplicationContext(),about.class);
startActivity(intentAbout);
}
});
}
// Methods to handleClick Event of Sign In Button
public void signIn(View V)
{
final Dialog dialog = new Dialog(homeActivity.this);
dialog.setContentView(R.layout.login);
dialog.setTitle("Login");
// get the Refferences of views
final EditText editTextUserName=(EditText)dialog.findViewById(R.id.editTextUserNameToLogin);
final EditText editTextPassword=(EditText)dialog.findViewById(R.id.editTextPasswordToLogin);
Button btnSignIn=(Button)dialog.findViewById(R.id.buttonSignIn);
// Set On ClickListener
btnSignIn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// get The User name and Password
String userName=editTextUserName.getText().toString();
String password=editTextPassword.getText().toString();
// fetch the Password form database for respective user name
String storedPassword=loginDataBaseAdapter.getSinlgeEntry(userName);
// check if the Stored password matches with Password entered by user
if(password.equals(storedPassword))
{
Toast.makeText(homeActivity.this, "Welcome," + userName, Toast.LENGTH_LONG).show();
dialog.dismiss();
Intent mainact=new Intent(getApplicationContext(),MainActivity.class);
mainact.putExtra("priceEdit", "floatvalue");
mainact.putExtra("pumpEdit", "floatvalue");
startActivity(mainact);
}
else
{
Toast.makeText(homeActivity.this, "User Name or Password does not match", Toast.LENGTH_LONG).show();
}
}
});
dialog.show();
}
@Override
protected void onDestroy() {
super.onDestroy();
// Close The Database
loginDataBaseAdapter.close();
}
}
这是我的MainActivity.java代码
public class MainActivity extends Activity {
Button saveButton = null;
EditText dateEdit;
EditText priceEdit;
EditText pumpEdit;
TextView costView;
EditText odometerEdit;
TextView fconView;
public boolean isNumeric(String str)
{
return str.matches("-?\\d+(\\.\\d+)?");
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Bundle bundle = getIntent().getExtras();
float price = Float.parseFloat(bundle.getString("priceEdit"));
float pump = Float.parseFloat(bundle.getString("pumpEdit"));
final float costView = (price * pump);
dateEdit = (EditText)findViewById(R.id.date);
priceEdit = (EditText)findViewById(R.id.fuelprice);
pumpEdit = (EditText)findViewById(R.id.fuelpump);
saveButton = (Button) findViewById(R.id.saveBTN);
saveButton.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
DBAdapter dbAdaptor = new DBAdapter(getApplicationContext());
try
{
dbAdaptor.open();
String date = dateEdit.getText().toString();
String price = priceEdit.getText().toString();
String pump = pumpEdit.getText().toString();
String cost = Float.toString(costView);
String odometer = odometerEdit.getText().toString();
String fcon = fconView.getText().toString();
dbAdaptor.insertLog(date, price, pump, cost, odometer, fcon);
}
catch(Exception e){
Log.d("Fuel Log", e.getMessage());
}
finally
{
if(dbAdaptor != null)
dbAdaptor.close();
}
}
});
}//oncreate
}//main
这是我的homescreen.xml代码
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center_vertical"
>
<Button
android:id="@+id/buttonSignIN"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Sign In"
android:onClick="signIn"/>
<Button
android:id="@+id/buttonSignUP"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Sign Up" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/home" />
<Button
android:id="@+id/aboutBTN"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="About" />
</LinearLayout>
这是我的activity_main.xml
的代码<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:orientation="vertical"
android:layout_height="fill_parent"
tools:context=".MainActivity" >
<TableLayout
android:id="@+id/tableLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:stretchColumns="1">
<TableRow
android:id="@+id/tableRow1"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="@+id/datetxtview"
android:text="@string/date"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<EditText
android:id="@+id/date"
android:text=""
android:inputType="date"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</EditText>
</TableRow>
<TableRow
android:id="@+id/tableRow2"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/fuelpricetxtview"
android:text="@string/fuelprice"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<EditText
android:id="@+id/fuelprice"
android:text=""
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</EditText>
</TableRow>
<TableRow
android:id="@+id/tableRow3"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/fuelpumptxtview"
android:text="@string/fuelpump"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<EditText
android:id="@+id/fuelpump"
android:text=""
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</EditText>
</TableRow>
<TableRow
android:id="@+id/tableRow4"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/totalcosttxtview"
android:text="@string/totalcost"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/tcost"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="" />
</TableRow>
<TableRow
android:id="@+id/tableRow5"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/odometertxtview"
android:text="@string/odometer"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<EditText
android:id="@+id/odometer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10" >
<requestFocus />
</EditText>
</TableRow>
<TableRow
android:id="@+id/tableRow6"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/fctxtview"
android:text="@string/fc"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/fcon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="" />
</TableRow>
</TableLayout>
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<Button
android:id="@+id/saveBTN"
android:text="@string/save"
android:layout_width="wrap_content"
android:layout_height="60px" >
</Button>
<Button
android:id="@+id/cancelBTN"
android:text="@string/cancel"
android:layout_width="wrap_content"
android:layout_height="60px" >
</Button>
</LinearLayout>
</LinearLayout>
答案 0 :(得分：3)
你有
Intent mainact=new Intent(getApplicationContext(),MainActivity.class);
startActivity(mainact);
您没有使用意图
将任何值传递给MainActivity更改为
Intent mainact=new Intent(HomeActivity.this,MainActivity.class);
mainact.putExtra("priceEdit","floatvalue");
mainact.putExtra("pumpEdit","floatvalue");
startActivity(mainact);
您尚未初始化dateEdit,priceEdit,pumpEdit。
setContentView(R.layout.activity_main);
Bundle bundle = getIntent().getExtras();
float price = Float.parseFloat(bundle.getString("priceEdit"));
float pump = Float.parseFloat(bundle.getString("pumpEdit"));
final float costView = (price * pump);
dateEdit= (EditText)findViewById(R.id.date);
priceEdit =(EditText)findViewById(R.id.fuelprice);
pumpEdit =(EditText)findViewById(R.id.fuelpump);
答案 1 :(得分：0)
在mainactivity.java中更改您的代码，如下所示。所有初始化必须在'setContentView(R.layout.activity_main);'
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Bundle bundle = getIntent().getExtras();
float price = Float.parseFloat(bundle.getString("priceEdit"));
float pump = Float.parseFloat(bundle.getString("pumpEdit"));
final float costView = (price * pump);