[英]editText.getText().toString returns empty
I'm new to Android and with the help of this site I've put together this code : 我是Android的新手,在此网站的帮助下,我将以下代码组合在一起:
java: Java的:
public class Activity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity);
String input1 = ((EditText) findViewById(R.id.editText)).getText().toString().trim();
TextView TextView = (TextView) findViewById(R.id.textView);
if (input1.length() == 0) {
TextView.setText("empty");
}
else {
TextView.setText(input1);
}
}
}
xml: XML:
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="number"
android:ems="10"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:id="@+id/editText"
android:layout_alignParentTop="true"
android:hint="text" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/editText"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="28dp"
android:layout_marginStart="28dp"
android:layout_marginTop="20dp"
android:id="@+id/textView" />
But the textView shows empty when I type , tried a lot of things but nothing worked . 但是当我输入文本时,textView显示为空,尝试了很多事情,但没有任何作用。
What I'm trying to do is get the value of editText and store it in a variable so I can work with it . 我想做的是获取editText的值并将其存储在变量中,以便我可以使用它。 I used a textView to see if it works but returns empty .
我使用了textView来查看它是否有效,但返回空值。 I want the value to be updated real time , just like Android default calculator app .
我希望该值能够实时更新,就像Android默认计算器应用程序一样。
EDIT 编辑
For my purpose I had to put a textWatcher. 为了我的目的,我不得不放置一个textWatcher。
public class Activity extends AppCompatActivity {
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity);
EditText editText = (EditText) findViewById(R.id.editText);
textView = (TextView) findViewById(R.id.textView);
editText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
textView.setText(s);
}
@Override
public void afterTextChanged(Editable s) {
}
});
}
}
You didnt cast the java file properly... 您没有正确投射Java文件...
TextView TextView = (TextView) findViewById(R.id.textView);
try replacing with 尝试替换为
TextView textView = (TextView) findViewById(R.id.textView);
Change your code to the following : 将您的代码更改为以下内容:
public class Activity extends AppCompatActivity {
EditText ed;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity);
ed= (EditText) findViewById(R.id.editText);
TextView TextView = (TextView) findViewById(R.id.textView);
String input1 = ed.getText().toString().trim();
if (input1.length() == 0) {
TextView.setText("empty");
}
else {
TextView.setText(input1);
}
}
}
Hope it works well :) 希望它运作良好:)
As pointed out by @Selvin, a Listener for text changes in the EditText would help. 正如@Selvin指出的那样,EditText中的文本更改侦听器将有所帮助。
TextWatcher textWatcher = new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (charSequence.length() == 0) {
TextView.setText("empty");
}
else {
TextView.setText(charSequence);
}
}
@Override
public void afterTextChanged(Editable editable) {
}
};
EditText editText = (EditText) findViewById(R.id.editText);
editText.addTextChangedListener(textWatcher);
But please remove the Listener ( textView.removeTextChangedListener(textWatcher);
) when you're done, as there's a potential for a memory leak here. 但请在完成后删除侦听器(
textView.removeTextChangedListener(textWatcher);
),因为此处可能会发生内存泄漏。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.