我一直在努力让这个工作,甚至完全按照教程所说的那样复制和粘贴代码,但它似乎不起作用。我知道问题出在MainActivity或DisplayMessageActivity上,但我看不出有什么问题。我还在与MainActivity相同的文件夹中安装了DisplayMessageActivity。Android的第一个应用教程问题
我收到以下错误。
DisplayMessageActivity
Gradle: error: cannot find symbol class SuppressLint
Gradle: error: package R does not exist
Gradle: error: cannot find symbol variable NavUtils
MainActivity
Gradle: error: cannot find symbol class DisplayMessageActivity
我一直在摆弄这一段时间,无法弄清楚我做错了什么。任何帮助深表感谢。
我有什么,
AndroidManifest.xml中
~snip~
<activity
android:name="com.example.myfirstapp.DisplayMessageActivity"
android:label="@string/title_activity_display_message"
android:parentActivityName="com.example.myfirstapp.MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.myfirstapp.MainActivity" />
</activity>
~snip~
DisplayMessageActivity
import android.app.Activity;
import android.os.Build;
import android.os.Bundle;
import android.view.MenuItem;
public class DisplayMessageActivity extends Activity {
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_message);
// Make sure we're running on Honeycomb or higher to use ActionBar APIs
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
// Show the Up button in the action bar.
getActionBar().setDisplayHomeAsUpEnabled(true);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}
MainActivity
package com.example.myfirstapp;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
UPDATE
Juned和Peter是正确的。它不能马上工作的唯一原因是因为我弄乱了其他东西。多谢你们!
做'Ctrl' +'Shift' +'O'先安排你的进口。 –
我有同样的问题,但我似乎无法找到这个'build.gradle'文件,我正在使用IntelliJ IDEA 13.1.1 – Baig