java 从edittext获取整数值
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Get integer value from edittext
提问by theduman
When I try to run the code below, my program has stops. I want this code to get the value from edittextbut it′s not working as I expected it. What am I doing wrong?
当我尝试运行下面的代码时，我的程序停止了。我希望这段代码从中获取值，edittext但它没有按我预期的那样工作。我究竟做错了什么？
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button sum = (Button) findViewById(R.id.button1);
Button cancel = (Button) findViewById(R.id.button2);
final EditText from = (EditText) findViewById(R.id.editText1);
final EditText upto = (EditText) findViewById(R.id.editText2);
final EditText runsum = (EditText) findViewById(R.id.editText3);
final int f = Integer.parseInt(from.getText().toString());
final int u = Integer.parseInt(upto.getText().toString());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
Here is my LogCat sorry for mess :/
这是我的 LogCat 抱歉弄乱了：/
08-28 19:34:44.241: E/Trace(3346): error opening trace file: No such file or directory (2)
08-28 19:34:44.780: D/AndroidRuntime(3346): Shutting down VM
08-28 19:34:44.780: W/dalvikvm(3346): threadid=1: thread exiting with uncaught exception(group=0x40a13300)
08-28 19:34:44.790: E/AndroidRuntime(3346): FATAL EXCEPTION: main
08-28 19:34:44.790: E/AndroidRuntime(3346): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.project/com.example.project.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.ActivityThread.access0(ActivityThread.java:130)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.os.Handler.dispatchMessage(Handler.java:99)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.os.Looper.loop(Looper.java:137)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.ActivityThread.main(ActivityThread.java:4745)
08-28 19:34:44.790: E/AndroidRuntime(3346): at java.lang.reflect.Method.invokeNative(Native Method)
08-28 19:34:44.790: E/AndroidRuntime(3346): at java.lang.reflect.Method.invoke(Method.java:511)
08-28 19:34:44.790: E/AndroidRuntime(3346): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-28 19:34:44.790: E/AndroidRuntime(3346): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-28 19:34:44.790: E/AndroidRuntime(3346): at dalvik.system.NativeStart.main(Native Method)
08-28 19:34:44.790: E/AndroidRuntime(3346): Caused by: java.lang.NumberFormatException: Invalid int: ""
08-28 19:34:44.790: E/AndroidRuntime(3346): at java.lang.Integer.invalidInt(Integer.java:138)
08-28 19:34:44.790: E/AndroidRuntime(3346): at java.lang.Integer.parseInt(Integer.java:359)
08-28 19:34:44.790: E/AndroidRuntime(3346): at java.lang.Integer.parseInt(Integer.java:332)
08-28 19:34:44.790: E/AndroidRuntime(3346): at com.example.project.MainActivity.onCreate(MainActivity.java:25)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.Activity.performCreate(Activity.java:5008)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
08-28 19:34:44.790: E/AndroidRuntime(3346): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
08-28 19:34:44.790: E/AndroidRuntime(3346): ... 11 more
08-28 19:35:10.560: E/Trace(3394): error opening trace file: No such file or directory (2)
08-28 19:35:11.629: D/gralloc_goldfish(3394): Emulator without GPU emulation detected.
08-28 19:48:19.295: I/Choreographer(3394): Skipped 41 frames! The application may be doing too much work on its main thread.
回答by Bartosz Przybylski
The problem seems that when Activity is bringed to front there is no value in EditText. Integer parser don't know how to parse empty String, so Exception is thrown.
问题似乎是，当 Activity 出现在前面时，EditText. 整数解析器不知道如何解析空字符串，所以抛出异常。
You need to check for existing of text in that EditTextbefore parsing
EditText在解析之前，您需要检查其中是否存在文本
final int f = -1; // or other invalid value
if (from.getText().toString().length() > 0)
f = Integer.parseInt(from.getText().toString());
Similarly for other EditText
同样对于其他 EditText
回答by thepoosh
as you can see from your Logcat:
正如您从 Logcat 中看到的：
08-28 19:34:44.790: E/AndroidRuntime(3346): Caused by: java.lang.NumberFormatException: Invalid int: ""
08-28 19:34:44.790: E/AndroidRuntime(3346): 引起: java.lang.NumberFormatException: Invalid int: ""
there was an empty input that couldn't be converted into an int.
有一个空输入无法转换为int.
try validating user input.
尝试验证用户输入。
回答by Kumar Vivek Mitra
-Please check the value of EditText, is it a validintegervalue or not.
-请检查的值EditText，它是一个有效的integer值或没有。
Try out this code:
试试这个代码：
int i = 0;
try{
i = Integer.parseInt(from.getText().toString());
}catch(NumberFormatException ex){
System.out.println("Value at TextView is not a valid integer");
}
