在 oncreate 方法之外使用布局参数不起作用
Using layoutparams outside oncreate method doesn't work
我试图在单击按钮时将我的 LinearLayout 高度更改为父布局的 50%。我用 LinearLayout.LayoutParams 尝试了它,但是如果我在 buttonClicked 从 onCreate 之外的方法调用它时它不会改变我的布局的高度。但是,如果我将 LinearLayout.LayoutParams 保留在 onCreate 中,那么它就可以工作。单击按钮时如何操作?
此代码有效:
public class ViewReport extends AppCompatActivity {
Button button;
LinearLayout layout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_report);
button=(Button) findViewById(R.id.button);
layout=(LinearLayout) findViewById(R.id.fold);
final LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) layout.getLayoutParams();
lp.height = 0;
lp.width=LinearLayout.LayoutParams.MATCH_PARENT;
lp.weight=0.5f;
}
}
此代码无效:
public class ViewReport extends AppCompatActivity {
Button button;
LinearLayout layout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_report);
button=(Button) findViewById(R.id.button);
layout=(LinearLayout) findViewById(R.id.fold);
}
public void Click(View view)
{
Toast.makeText(getApplicationContext(),"tapped",Toast.LENGTH_LONG).show();
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) layout.getLayoutParams();
lp.height = 0;
lp.width=LinearLayout.LayoutParams.MATCH_PARENT;
lp.weight=0.5f;
}
}
布局XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="me.imbishal.imageblur.ViewReport"
android:weightSum="1">
<LinearLayout
android:id="@+id/fold"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@drawable/profilepageback"
android:orientation="vertical">
<EditText
android:id="@+id/editText4"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_marginBottom="3dp"
android:background="@drawable/my_button"
android:ems="10"
android:inputType="textPersonName" />
<EditText
android:id="@+id/editText3"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_marginBottom="5dp"
android:background="@drawable/my_button"
android:ems="10"
android:inputType="textPersonName" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:background="@drawable/just_border"
android:onClick="Click"
android:text="Button" />
</LinearLayout>
您更改了 LayoutParams 但尚未设置它们。添加这一行
layout.setLayoutParams(lp);
我试图在单击按钮时将我的 LinearLayout 高度更改为父布局的 50%。我用 LinearLayout.LayoutParams 尝试了它,但是如果我在 buttonClicked 从 onCreate 之外的方法调用它时它不会改变我的布局的高度。但是,如果我将 LinearLayout.LayoutParams 保留在 onCreate 中,那么它就可以工作。单击按钮时如何操作?
此代码有效:
public class ViewReport extends AppCompatActivity {
Button button;
LinearLayout layout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_report);
button=(Button) findViewById(R.id.button);
layout=(LinearLayout) findViewById(R.id.fold);
final LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) layout.getLayoutParams();
lp.height = 0;
lp.width=LinearLayout.LayoutParams.MATCH_PARENT;
lp.weight=0.5f;
}
}
此代码无效:
public class ViewReport extends AppCompatActivity {
Button button;
LinearLayout layout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_report);
button=(Button) findViewById(R.id.button);
layout=(LinearLayout) findViewById(R.id.fold);
}
public void Click(View view)
{
Toast.makeText(getApplicationContext(),"tapped",Toast.LENGTH_LONG).show();
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) layout.getLayoutParams();
lp.height = 0;
lp.width=LinearLayout.LayoutParams.MATCH_PARENT;
lp.weight=0.5f;
}
}
布局XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="me.imbishal.imageblur.ViewReport"
android:weightSum="1">
<LinearLayout
android:id="@+id/fold"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@drawable/profilepageback"
android:orientation="vertical">
<EditText
android:id="@+id/editText4"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_marginBottom="3dp"
android:background="@drawable/my_button"
android:ems="10"
android:inputType="textPersonName" />
<EditText
android:id="@+id/editText3"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_marginBottom="5dp"
android:background="@drawable/my_button"
android:ems="10"
android:inputType="textPersonName" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:background="@drawable/just_border"
android:onClick="Click"
android:text="Button" />
</LinearLayout>
您更改了 LayoutParams 但尚未设置它们。添加这一行
layout.setLayoutParams(lp);