我在这里运行教程:https://developer.android.com/training/basics/firstapp/starting-activity.html并在标题为"开始另一项活动"的页面上,标题为"构建意图"
按照说明操作后
在MainActivity.java中,将下面显示的代码添加到
sendMessage()
,
MainActivity.java 如下所示:
package com.example.myfirstapp;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import static android.provider.AlarmClock.EXTRA_MESSAGE;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/** Called when the user clicks the Send button */
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);
}
}
然后说明说要按 Alt / Enter 导入缺少的类。按 Alt / Enter 后,代码看起来像这样(唯一的变化是在导入中):
package com.example.myfirstapp;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import static android.provider.AlarmClock.EXTRA_MESSAGE;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); package com.example.myfirstapp;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/** Called when the user clicks the Send button */
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);
}
}
}
/** Called when the user clicks the Send button */
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);
}
}
然后工作室再次按 Alt / Enter (我想解决EXTRA_MESSAGE
)。所以我做了。这会创建一个对话框来创建常量字段' EXTRA_MESSAGE'"。但我不知道给它带来什么价值。
第一次按 Alt / Enter 不会产生预期的结果。该教程说导入应该如下所示:
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
现在我对下一步该做什么感到困惑。
有人可以对教程中可能缺少的内容发表评论吗?