Question

我正在尝试将LinearLayout作为子项添加到另一个LinearLayout组件，但它根本不会显示在屏幕上。

XML：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/ReceivedMessage"
android:background="@android:color/holo_blue_light"
android:visibility="visible"
tools:showIn="@layout/content_chat">

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:srcCompat="@mipmap/ic_launcher"
    android:id="@+id/ProfilePicture"
    android:layout_weight="1" />

<TextView
    android:text="   Message"
    android:layout_width="305dp"
    android:layout_height="match_parent"
    android:id="@+id/MessageText"
    android:gravity="center_vertical" />
</LinearLayout>

代码：

Button testMessageButton = (Button) findViewById(R.id.TestMessageButton);
    testMessageButton.setOnClickListener(new View.OnClickListener()
    {
        public void onClick(View view)
        {
            LinearLayout msgLayout = (LinearLayout) findViewById(R.id.MessageLayout);

            LayoutInflater vi = (LayoutInflater)getBaseContext()
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View v = vi.inflate(R.layout.message_received, msgLayout, false);


            msgLayout.addView(v);
        }
    });

导致组件不出现在屏幕上的原因是什么？

Answer 1

您的问题不正确，但我会以两种不同的方式回答

首先，如果要添加的LinearLayout位于不同的xml文件中，那么您可以将xml文件充气并将其添加到Activity类中的父LinearLayout，如下所示

Button testMessageButton = (Button) findViewById(R.id.TestMessageButton);
testMessageButton.setOnClickListener(new View.OnClickListener(){
    public void onClick(View view){
        LinearLayout msgLayout = (LinearLayout) findViewById(R.id.MessageLayout);

        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
        LayoutInflater vi = (LayoutInflater)getBaseContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View v = vi.inflate(R.layout.message_received, null);
        v.setLayoutParams(params);

        msgLayout.addView(v);
    }
});

我已更新我的解决方案。部分问题出在您的布局文件

中

这是活动类

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;

public class MainActivity extends AppCompatActivity {

private LinearLayout mainLayout;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mainLayout = (LinearLayout)findViewById(R.id.main_layout);
    Button addChatButton = (Button)findViewById(R.id.add_chat);
    addChatButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
            LayoutInflater vi = (LayoutInflater)getBaseContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            LinearLayout mView = (LinearLayout)vi.inflate(R.layout.test_layout, mainLayout, false);
            mView.setLayoutParams(params);
            mainLayout.addView(mView);
        }
    });
  }
}

Activity类

的xml布局文件

<?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:id="@+id/main_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.inducesmile.mylinear.MainActivity">

<Button
    android:id="@+id/add_chat"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="80dp"
    android:text="@string/add_chat"
    android:layout_gravity="center|center_horizontal"/>
</LinearLayout>

最后，包含要膨胀的Linearlayout的布局文件并添加到根LinearLayout。

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/ReceivedMessage"
android:background="@android:color/holo_blue_light"
android:visibility="visible">

<ImageView
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:src="@mipmap/ic_launcher"
    android:id="@+id/ProfilePicture"
    android:layout_weight="2" />

<TextView
    android:text="@string/message"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:id="@+id/MessageText"
    android:layout_weight="7"
    android:paddingTop="14dp"
    android:paddingBottom="14dp"
    android:gravity="center_vertical" />

</LinearLayout>

Answer 2

基于Inducesmile，如果将子容器添加到父容器中，则可能会出现问题，因为父容器未放置在滚动视图内，因此如果要进行制作，则所有要添加的子项都不会显示确保已添加的视图在添加任何子项

后调用parentlayout.getChildCount（）

LayoutInflater不适用于Android

2 个答案: