为什么自定义控件是不是在activity_main.xml中可见 [英] Why Custom Control is not visible in activity_main.xml
问题描述
这是新的code，它不会抛出异常，但我看不到我的自定义控制秒。这是新的code：
This is the new code, It doesn't throw exceptions, but I can't see my custom control "Second". This is the new code:
activity_main.xml中：
activity_main.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/layoutRoot"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/L1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical" >
<Button
android:id="@+id/addButton"
android:layout_width="74dp"
android:layout_height="wrap_content"
android:text="Add" />
<EditText
android:id="@+id/newEditText"
android:layout_width="174dp"
android:layout_height="wrap_content"
android:layout_weight="3.24"
android:ems="10"
android:inputType="text" />
</LinearLayout>
<LinearLayout
android:id="@+id/List"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
</LinearLayout>
</LinearLayout>
这是自定义控制：second.xml：
This is the custom control: second.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/secodView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Button
android:id="@+id/expandButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.44"
android:text = "Expand"/>
<TextView
android:id="@+id/txtView"
android:layout_width="253dp"
android:layout_height="wrap_content"
android:layout_weight="0.56"
android:ems="10"
android:text = "LOL"/>
</LinearLayout>
<RadioGroup
android:id="@+id/ratingRadioGroup"
android:layout_width="321dp"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<RadioButton
android:id="@+id/likeButton"
android:layout_width="145dp"
android:layout_height="wrap_content"
android:checked="true"
android:text="Like" />
<RadioButton
android:id="@+id/dislikeButton"
android:layout_width="147dp"
android:layout_height="wrap_content"
android:text="Dislike" />
</RadioGroup>
</LinearLayout>
Second.java类：
Second.java class:
public class Second extends ViewGroup
{
private Button mExpandButton;
private RadioButton mLikeButton;
private RadioButton mDislikeButton;
private TextView mText;
private RadioGroup mLikeGroup;
private ViewGroup vGroup;
OnClickListener myClickListener = new OnClickListener()
{
@Override
public void onClick(View v)
{
String s= mExpandButton.getText().toString();
if (s.equals("One Click"))
mExpandButton.setText("Other Click");
else
mExpandButton.setText("One Click");
}
};
OnCheckedChangeListener myCkeckListener = new OnCheckedChangeListener()
{
@Override
public void onCheckedChanged(RadioGroup group, int checkedId)
{
if (mLikeButton.isChecked())
mText.setText("I Like it");
if (mDislikeButton.isChecked())
mText.setText("I Don't Like it");
}
};
public Second(Context context)
{
super(context);
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = LayoutInflater.from(context).inflate(R.layout.second, this, true);
mText = (TextView)this.findViewById(R.id.txtView);
mExpandButton = (Button) this.findViewById(R.id.expandButton);
mLikeGroup = (RadioGroup)this.findViewById(R.id.ratingRadioGroup);
mExpandButton.setOnClickListener(myClickListener);
mLikeGroup.setOnCheckedChangeListener(myCkeckListener);
//inflater.inflate(R.layout.second, null);
}
@Override
protected void onLayout(boolean arg0, int arg1, int arg2, int arg3, int arg4)
{
// TODO Auto-generated method stub
}
}
ActivityMain.java类，这里的活动被启动：
ActivityMain.java class, where the activity gets started:
public class MainActivity extends Activity
{
protected LinearLayout mList;
protected EditText mEditText;
protected Button mButton;
Second[] sec;
boolean unavez;
OnClickListener myClickListener = new OnClickListener()
{
@Override
public void onClick(View v)
{
}
};
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mList = (LinearLayout)findViewById(R.id.List);
mEditText = (EditText)findViewById(R.id.newEditText);
mButton = (Button)findViewById(R.id.addButton);
sec = new Second[4];
unavez = true;
for (int i=0; i<4; i++)
sec[i]= new Second(this);
}
@Override
protected void onStart()
{
super.onStart();
}
@Override protected void onResume()
{
super.onResume();
if (!unavez)
return;
for (int i=0; i<4; i++)
{
mList.addView(sec[i]);
//setContentView(sec[i]);
}
unavez = false;
}
@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;
}
}
在运行时，我可以看到按钮和activity_main.xml中的EditText上，但我看不到我的second.xml自定义控件。如果我使用该行的setContentView（秒[I]），而不是mList.addView（SEC [I]）在onResume（），事情变得更糟糕：在与的EditText activity_main.xml中的按钮是不可见的，并得到了一个空白布局。
When running, I can see the Button and the EditText in activity_main.xml, but I can't see my custom control in second.xml. If I use the line setContentView(sec[i]) instead of mList.addView(sec[i]) in onResume(), it gets worse: the EditText and the Button in activity_main.xml aren't visible and I get a blank layout.
我怎么可以加我的自定义控件activity_main.xml中，并使其对用户可见的？
How can I add my custom control to activity_main.xml and make it visible to user?
推荐答案
您选择让二从的ViewGroup 。既然你这样做，二必须真正的的ViewGroup ，以一个真正的 onLayout（）执行情况和其他一切与作为一个的ViewGroup 随之而来。不要只是随机覆盖与无为的实现方法，然后抱怨的时候什么也不做的实现什么也不做。
You elected to have Second inherit directly from ViewGroup. Since you did that, Second needs to be a real ViewGroup, with a real onLayout() implementation and everything else that goes along with being a ViewGroup. Do not just randomly override methods with do-nothing implementations, then complain when the do-nothing implementations do nothing.
创建自定义控件是Android的一个比较高级的主题。初来乍到的Android应侧重于其他的解决方案，以任何问题，他们认为自定义控制会以某种方式解决。
Creating "custom controls" is a relatively advanced topic in Android. Newcomers to Android should focus on other solutions to whatever problem they think a "custom control" will somehow solve.
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