[英]How do I make this into one activity?
I'm doing this tutorial, but I'm having some trouble with understanding how to make this into one activity. 我正在做本教程,但是在理解如何使它成为一项活动时遇到了一些麻烦。 (In the tutorial, you would have Main Activity and Display Message Activity, but for my purposes, I need it to be in one activity) I understand how everything works, but I just can't figure out how to make this into one activity. (在本教程中,您将具有“主活动”和“显示消息活动”,但出于我的目的,我需要将其置于一个活动中)我了解所有工作原理,但我只是想不通如何将其变成一个活动。 Any help is appreciated! 任何帮助表示赞赏!
Here is the tutorial I'm working on: https://developer.android.com/training/basics/firstapp/building-ui.html 这是我正在研究的教程: https : //developer.android.com/training/basics/firstapp/building-ui.html
And I'll include my code below, but it's probably easier to see where I am in the tutorial (I'm at the step, "Starting Another Activity"). 并且我将在下面包含我的代码,但是可能更容易看出我在教程中的位置(我正在执行“开始另一个活动”)。
fragment_main.xml fragment_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<EditText android:id="@+id/edit_message"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="@string/edit_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_send"
android:onClick="sendMessage" />
</LinearLayout>
MainActivity.java MainActivity.java
package com.example.helloworld;
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.content.Intent;
import android.os.Build;
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);
if (savedInstanceState == null) {
getFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
@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;
}
@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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
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);
}
}
If you want to change the layout when a button is pressed and display hello world
you can use your fragment PlaceholderFragment
inside your MainActivity
to display it 如果要在按下按钮时更改布局并显示hello world
,可以在MainActivity
使用片段PlaceholderFragment
进行显示
sample: 样品:
public void sendMessage(View view) {
getFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
Fragment: 分段:
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
TextView tx = (TextView)rootView.findViewById(R.id.hello_world);
tx.setText(editText.getText().toString());
return rootView;
}
}
In your fragment_main.xml
在你的fragment_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/start_screen"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<TextView
android:id="@+id/hello_world"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="40sp"
android:textAppearance="?android:attr/textAppearanceMedium" />
</LinearLayout>
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