問題描述
我的代碼有問題.當我有一個空白的 editText 字段時，它一直在崩潰.這段代碼在我的應用程序的設置中，可以正常工作，但是當有一個空白字段時，它會使程序崩潰.這是它的代碼.請不要苛刻，因為這是我的第一個 android 應用程序.因此，如果有人知道如何解決空白編輯文本字段問題，將不勝感激！(有關如何改進應用程序的任何其他評論都會有所幫助).
I have a problem with my code. It keeps on crashing when i have a blank editText field. This bit of code is in the settings of my app and works the data fine but when there is a blank field it crashes the program. Here's the code for it. Please don't be harsh because it is my 1st android app. So if anyone knows how to solves the blank edit text field problem that would be greatly appreciated! (Any other comments on how to improve the app would be a help to).
干杯
package com.cleanyet.cyv100fp;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class sTasks extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.tasks);
/*Sets Up the Variables*/
Button done = (Button) findViewById(R.id.done1);
EditText t1 = (EditText)findViewById(R.id.tbTask1);
EditText t2 = (EditText)findViewById(R.id.tbTask2);
EditText t3 = (EditText)findViewById(R.id.tbTask3);
EditText t4 = (EditText)findViewById(R.id.tbTask4);
EditText t5 = (EditText)findViewById(R.id.tbTask5);
String FILENAME1 = "stask1";
String FILENAME2 = "stask2";
String FILENAME3 = "stask3";
String FILENAME4 = "stask4";
String FILENAME5 = "stask5";
String task1 = null;
String task2 = null;
String task3 = null;
String task4 = null;
String task5 = null;
String edit = "Edit Task";
/*Fixes the Blank Field bug*/
/*Sets up the file input*/
FileInputStream fis = null;
/*Gets the tasks set previously*/
/*Task 1 set up*/
try {
fis = openFileInput(FILENAME1);
byte[] dataArray = new byte[fis.available()];
while (fis.read(dataArray) != -1){
task1 = new String(dataArray);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
try {
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (task1.toString().length() < 0) {
task1.toString();
t1.setText(task1);
}
else {
t1.setText(edit);
}
/*Task 2 set up*/
try {
fis = openFileInput(FILENAME2);
byte[] dataArray = new byte[fis.available()];
while (fis.read(dataArray) != -1){
task2 = new String(dataArray);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
try {
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (task2.toString().length() < 0) {
task2.toString();
t2.setText(task2);
}
else {
t2.setText(edit);
}
/*Task 3 set up*/
try {
fis = openFileInput(FILENAME3);
byte[] dataArray = new byte[fis.available()];
while (fis.read(dataArray) != -1){
task3 = new String(dataArray);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
try {
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (task3.toString().length() < 0) {
task3.toString();
t3.setText(task3);
}
else {
t3.setText(edit);
}
/*Task 4 set up*/
try {
fis = openFileInput(FILENAME4);
byte[] dataArray = new byte[fis.available()];
while (fis.read(dataArray) != -1){
task4 = new String(dataArray);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
try {
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (task4.toString().length() < 0) {
task4.toString();
t4.setText(task4);
}
else {
t4.setText(edit);
}
/*Task 5 set up*/
try {
fis = openFileInput(FILENAME5);
byte[] dataArray = new byte[fis.available()];
while (fis.read(dataArray) != -1){
task5 = new String(dataArray);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
try {
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (task5.toString().length() < 0) {
task5.toString();
t5.setText(task5);
}
else {
t5.setText(edit);
}
/*When changes have been made and done is clicked*/
done.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
/*Sets up the Variables*/
EditText t1 = (EditText)findViewById(R.id.tbTask1);
EditText t2 = (EditText)findViewById(R.id.tbTask2);
EditText t3 = (EditText)findViewById(R.id.tbTask3);
EditText t4 = (EditText)findViewById(R.id.tbTask4);
EditText t5 = (EditText)findViewById(R.id.tbTask5);
String tasks1 = t1.getText().toString();
String tasks2 = t2.getText().toString();
String tasks3 = t3.getText().toString();
String tasks4 = t4.getText().toString();
String tasks5 = t5.getText().toString();
String FILENAME1 = "stask1";
String FILENAME2 = "stask2";
String FILENAME3 = "stask3";
String FILENAME4 = "stask4";
String FILENAME5 = "stask5";
String task1 = tasks1;
String task2 = tasks2;
String task3 = tasks3;
String task4 = tasks4;
String task5 = tasks5;
String edit = "Go to settings to make this task.";
if (t1 != null){
t1.setText(edit);
/*t2.setText(edit);
t3.setText(edit);
t4.setText(edit);
t5.setText(edit);*/
};
/*Put if statement here to catch the empty field*/
/*Makes The Changes to the Tasks*/
try {
FileOutputStream fos1 = openFileOutput(FILENAME1, Context.MODE_PRIVATE);
fos1.write(task1.getBytes());
fos1.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
FileOutputStream fos2 = openFileOutput(FILENAME2, Context.MODE_PRIVATE);
fos2.write(task2.getBytes());
fos2.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
FileOutputStream fos3 = openFileOutput(FILENAME3, Context.MODE_PRIVATE);
fos3.write(task3.getBytes());
fos3.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
FileOutputStream fos4 = openFileOutput(FILENAME4, Context.MODE_PRIVATE);
fos4.write(task4.getBytes());
fos4.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
FileOutputStream fos5 = openFileOutput(FILENAME5, Context.MODE_PRIVATE);
fos5.write(task5.getBytes());
fos5.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
startActivity(new Intent("com.checkin.cyv100fp.settings"));
}
});
}
}
推薦答案
if (task1.toString().length() < 0) {
task1.toString();
t1.setText(task1);
}
else {
t1.setText(edit);
}
以上說的毫無意義.
首先 task1 是一個字符串，因此無需調用 toString() 將其轉換為一個.
Firstly task1 IS a string so there's no need to call toString() to convert it to one.
其次，您的條件語句 (if) 正在檢查 task1 的長度是否小于零......考慮一下.
Secondly, your conditional statement (if) is checking to see if task1 has a length less than zero....think about it.
第三，如果它確實有一個不可能的長度小于零，那么你再次調用 toString() (沒有變量來接收不可能小于零的結果)，然后你嘗試設置你的 t1 EditText 的文本.
Thirdly, if it does have an impossible length less than zero you then call toString() on it again (with no variable to receive the impossible less than zero result) and you then try to set the text of your t1 EditText.
可能是您的文件讀取失敗(可能是因為您稍后僅在 onClick(...) 方法中保存字符串).因為如果文件讀取失敗，您的 task 字符串將為 null，因此您需要在嘗試使用它們之前測試 null.
The chances are that your file reading is failing (probably because you only save the strings later in the onClick(...) method). Because your task strings will be null if the file reading fails then you need to test for null before trying to use them.
換句話說，您正在代碼中執行此操作...
In other words you're doing this in your code...
String task1 = null;
要修復我在開頭附上的那段代碼，請使用...
To fix the bit of code I enclosed at the beginning, use...
if (task1 != null) {
t1.setText(task1);
}
else {
t1.setText(edit);
}
...但最重要的是，確保您的文件中包含您需要讀取的字符串.
...but most importantly, make sure your files have the strings in them that you need to read.
這篇關于Android:當有一個空白的editText字段時，我的應用程序崩潰了的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！