TextView无法强制转换为EditText [英] TextView cannot be cast to EditText
本文介绍了TextView无法强制转换为EditText的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
第一次向这个网站发帖提问，所以我可能会犯一些错误！
First time posting a question to this site so I might make some mistakes!
我是新手编程并在Android中运行应用程序时遇到以下错误Studio：
I'm new to programming and getting the following error when running an application in Android Studio:
java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.EditText
造成此问题的代码是
EditText et = (EditText) findViewById(R.id.noteText);
我试图删除R.java文件并清理项目但它不起作用，任何帮助解决问题的人都会非常感激:)
I've tried to delete the R.java files and clean the project but it didn't work, any help solving the problem would be greatly appreciated :)
我可以添加任何其他可能是问题因素的文件或相关代码。
I can add any other files or relevant code that might be a factor in the problem.
编辑：将代码从文本视图更改为编辑文本后，我收到一个新错误。
After changing the code from text view to edit text I'm getting a new error.
Logcat：
08-03 20:08:04.413 29662-29662/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.toshiba.notetakingapp/com.example.toshiba.notetakingapp.NoteEditorActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2092)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117)
at android.app.ActivityThread.access$700(ActivityThread.java:134)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1218)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4867)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.toshiba.notetakingapp.NoteEditorActivity.onCreate(NoteEditorActivity.java:33)
at android.app.Activity.performCreate(Activity.java:5047)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2056)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117)
at android.app.ActivityThread.access$700(ActivityThread.java:134)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1218)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4867)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
at dalvik.system.NativeStart.main(Native Method)
xml文件，activity_note_editor：
The xml file, activity_note_editor:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<EditText
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="New Text"
android:id="@+id/noteText"
android:singleLine="false"
android:gravity="top"
android:inputType="textMultiLine"
/>
</RelativeLayout>
给出错误的文件，NoteEditorActivity：
The file that's giving the error, NoteEditorActivity:
public class NoteEditorActivity extends Activity {
private NoteItem note;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_note_editor);
Intent intent = this.getIntent();
note = new NoteItem();
note.setKey(intent.getStringExtra("key"));
note.setText(intent.getStringExtra("text"));
EditText et = (EditText) findViewById(R.id.noteText);
et.setText(note.getText());
et.setSelection(note.getText().length());
}
}
Mainactivity.java：
Mainactivity.java:
package com.example.toshiba.notetakingapp;
import android.app.ListActivity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import data.NoteItem;
import data.NotesDataSource;
import java.util.List;
public class MainActivity extends ListActivity {
private NotesDataSource datasource;
List<NoteItem> notesList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
datasource = new NotesDataSource(this);
refreshDisplay();
}
private void refreshDisplay() {
notesList=datasource.findAll();
ArrayAdapter<NoteItem> adapter =
new ArrayAdapter<NoteItem>(this,R.layout.list_item_layout,notesList);
setListAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_main, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_create) {
createNote();
return true;
}
return super.onOptionsItemSelected(item);
}
private void createNote() {
NoteItem note = NoteItem.getNew();
Intent intent = new Intent(this,NoteEditorActivity.class);
intent.putExtra("key",note.getKey());
intent.putExtra("key",note.getText());
startActivityForResult(intent,1001);
}
}
推荐答案
In你的xml，
更改
In your xml, change
<TextView
android:id="@+id/noteText"
.../>
到
<EditText
android:id="@+id/noteText"
.../>
希望这会有所帮助。
编辑：
您没有在意图中加入文字。 :)
You didn't put 'text' in the intent. :)
尝试更改
intent.putExtra("key",note.getKey());
intent.putExtra("key",note.getText());
到
intent.putExtra("key",note.getKey());
intent.putExtra("text",note.getText());
这篇关于TextView无法强制转换为EditText的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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