我有一个使用多个活动的应用。一项活动是手动输入一些值，我在该活动中有四个按钮。单击其中一个按钮时，它会启动一个新活动以获取输入。
问题是当运行此活动的get_input（）函数时，不会显示活动的布局。它应该从EditText获取十进制值。但我一直收到运行时错误＆＃34; Invalid Float＆＃34;＆＃34;＆＃34;。
如果我注释掉get_input（）函数，那么活动的布局就会很好。
这是xml文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/manually_entry" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Please enter the decimal Latitude"
android:singleLine="true"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Negative is South"
android:singleLine="true"
/>
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:inputType="numberDecimal|numberSigned"
android:id="@+id/enter_decimal_number" />
</LinearLayout>
这是调用活动：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.lat_long_manual_entry);
}
// manual entry dialog buttons
public void enter_lat_dec_deg(View v) {
Intent intent = new Intent(this.getApplicationContext(), ManuallyEnterNumbers.class);
startActivity(intent);
}
And here is the called activity that requests the actual input from the user :
package com.example.david.gpstest;
import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.TextView;
/**
* Created by david on 06/03/16.
*/
public class ManuallyEnterNumbers extends Activity {
private EditText input;
private float decimal_input;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.manually_enter_numbers);
}
@Override
protected void onStart() {
super.onStart();
}
@Override
protected void onResume() {
super.onResume();
get_input();
}
public void get_input() {
input = (EditText) findViewById(R.id.enter_decimal_number);
input.setOnEditorActionListener(new TextView.OnEditorActionListener() {
@Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
if (actionId == EditorInfo.IME_ACTION_DONE) {
decimal_input = Float.valueOf(input.getText().toString());
return true;
}
return false;
}
});
}
}
我在onStart（）方法中显示了函数get_input（），但是IO也在onResume（）方法中尝试了它，并且它也不起作用。
非常感谢任何帮助。
Thank You.
答案 0 :(得分：0)
（input.getText（）的toString（））Float.valueOf;
这里新手的常见错误是在尝试转换之前缺乏字符串清理。即使,（逗号）而不是作为小数部分分隔符输入的.（点），也会引发异常。因此，您只需要使字符串可转换（即通过检查内部的内容，将,替换为.等），更不用说您应该期待异常来使用try/catch来捕获它以避免应用你现在面临崩溃。
答案 1 :(得分：0)
android:inputType="numberDecimal|numberSigned"，所以您将获得一个带逗号的数字小键盘，并禁用空格。所以用户可以输入的是小数点和减号。正是你想要的。其次，您可以忘记onStart()和onResume()方法，并将所有内容都放在onCreate()中，然后它就会起作用。你的xml绝对没问题。您的调用活动也绝对正常，尽管使用intent.putExtra()和intent.getExtra()将decimal_input值传递回调用活动是个好主意。我已经发布了下面的调用活动和被调用活动的代码来帮助你。
public class ManualEntry extends Activity {
// private View layout;
// private PopupWindow enter_manual_dec_deg;
// LayoutInflater inflater;
// private EditText input;
// private float decimal_input;
// private String result;
static final int REQUEST_CODE = 1;
String button_pressed;
/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.lat_long_manual_entry);
}
@Override
protected void onResume() {
super.onResume();
}
// manual entry dialog buttons
public void enter_lat_dec_deg(View v) {
Intent intent = new Intent(this.getApplicationContext(), ManuallyEnterNumbers.class);
button_pressed = "lat_dec_deg";
intent.putExtra("Button pressed", button_pressed);
startActivityForResult(intent, REQUEST_CODE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE) {
if (resultCode == RESULT_OK) {
double result = data.getDoubleExtra("returnData", 0.0d);
if (result < -180 || result > 180) {
Toast.makeText(this, "Value outside range - Range is -180 to 180", Toast.LENGTH_LONG).show();
}
else {
DecimalFormat var = new DecimalFormat("###.########");
Toast.makeText(this, var.format(result), Toast.LENGTH_LONG).show();
disable_button(button_pressed);
}
}
}
}
void disable_button(String pressed_button) {
Button dec_deg_button = (Button) findViewById(R.id.button_lat_dec_deg);
Button d_m_s_button = (Button) findViewById(R.id.button_lat_deg_min_sec);
if (pressed_button != null) {
if (pressed_button == "lat_dec_deg" || button_pressed == "lat_d_m_s") {
dec_deg_button.setEnabled(false);
d_m_s_button.setEnabled(false);
}
}
}
}
/*
public void enter_lat_d_m_s (View v) {
}
public void enter_lon_dec_deg(View v) {
}
public void enter_lon_d_m_s(View v) {
}
*/
和被叫活动
package com.example.david.gpstest;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
/**
* Created by david on 06/03/16.
*/
public class ManuallyEnterNumbers extends Activity {
private EditText input;
private String inValue;
private double decimal_input;
private Bundle extras;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.manually_enter_numbers);
extras = getIntent().getExtras();
if (extras != null) {
String buttonPressed = extras.getString("Button pressed");
if (buttonPressed.contentEquals(buttonPressed) ) {
((TextView) findViewById(R.id.enter_decimal_number)).setHint("Decimal degrees of Latitude");
TextView title_text = (TextView) findViewById(R.id.manual_entry_hint);
title_text.setText("Please enter the decimal Latitude");
TextView hint_text = (TextView) findViewById(R.id.manual_entry_hint);
hint_text.setText("(Negative is South)");
}
}
get_input();
}
@Override
protected void onStart() {
super.onStart();
// get_input();
}
@Override
protected void onResume() {
super.onResume();
// get_input();
}
public void get_input() {
input = (EditText) findViewById(R.id.enter_decimal_number);
input.setOnEditorActionListener(new TextView.OnEditorActionListener(){
@Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
if (actionId == EditorInfo.IME_ACTION_DONE) {
// do stuff here
inValue = input.getText().toString();
if (inValue.isEmpty()) {
Toast.makeText(getApplicationContext(), "Enter a value", Toast.LENGTH_SHORT).show();
}
else {
// some input
decimal_input = Double.parseDouble(inValue);
Intent returnIntent = getIntent();
returnIntent.putExtra("returnData", decimal_input);
setResult(RESULT_OK, returnIntent);
finish();
}
}
return true;
}
});
/*
Intent returnIntent = getIntent();
returnIntent.putExtra("returnData", decimal_input);
setResult(RESULT_OK, returnIntent);
finish();
*/
}
}
我希望这会对你有所帮助。
David.