Add layout with parameters programmatically Android

问题

Hello I have a main screen.

<RelativeLayout 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"
tools:context=".MainActivity" >
<fragment
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.google.android.gms.maps.SupportMapFragment"/>
<ImageButton
    android:id="@+id/imageButton1"
    android:layout_width="55dp"
    android:layout_height="50dp"
    android:layout_alignParentTop="true"
    android:layout_marginTop="10dp"
    android:layout_toLeftOf="@+id/toggleButton1"
    android:background="@android:drawable/btn_default"
    android:contentDescription="@string/app_name"
    android:scaleType="centerCrop"
    android:src="@drawable/plus_grey" />

<LinearLayout
    android:id="@+id/lay"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_marginEnd="0dp"
    android:background="#A0FFFFFF"
    android:orientation="horizontal"
    android:visibility="invisible" >

    <TextView
        android:id="@+id/locinfo"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:textColor="@color/cherniy"
        android:textSize="20sp"
        android:visibility="visible" />
</LinearLayout>
</RelativeLayout>

And there is a imageButton

                    button = (ImageButton) findViewById(R.id.imageButton1);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v)  {
                if (bIcon == false) {
                    button.setImageResource(R.drawable.plus_yellow);                                                                   
                    m = myMap.addMarker(new MarkerOptions().position(myMap.getCameraPosition().target).draggable(true));                     
                    LinearLayout linLayout = (LinearLayout)findViewById(R.id.lay);
                    t = (TextView)findViewById(R.id.locinfo);                      
                    linLayout.setVisibility(View.VISIBLE);
                    t.setVisibility(View.VISIBLE);                      
                                bIcon = true;
                }
                else {
                    button.setImageResource(R.drawable.plus_grey);                                             
                    m.remove();
                    LinearLayout linLayout = (LinearLayout)findViewById(R.id.lay);
                    t.setVisibility(View.INVISIBLE);
                    linLayout.setVisibility(View.INVISIBLE);                        
                    bIcon = false;                
                }                             
            }
        });

I want to programmatically add

LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams((w*2)/3, LayoutParams.WRAP_CONTENT);

where w

display = getWindowManager().getDefaultDisplay(); 
@SuppressWarnings("deprecation")
w = display.getWidth();

But when I do like this

                button.setImageResource(R.drawable.plus_yellow);                                                                   
                m = myMap.addMarker(new MarkerOptions().position(myMap.getCameraPosition().target).draggable(true));                     
                LinearLayout linLayout = (LinearLayout)findViewById(R.id.lay);
                LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams((w*2)/3, LayoutParams.WRAP_CONTENT);
                linLayout.setLayoutParams(lp);
                t = (TextView)findViewById(R.id.locinfo);                      
                linLayout.setVisibility(View.VISIBLE);
                t.setVisibility(View.VISIBLE);                      
                bIcon = true;

My application crashes. Can you please tell how to programmatically create with my parameters (tied with the width and height of the screen of the device)? I will take any suggestions. Thank you.

回答1:

LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
    (w*2)/3, 
    LayoutParams.WRAP_CONTENT
);
linLayout.setLayoutParams(lp);

This will throw error because the LinearLayout is the child of Relative layout, so you have to set RelativeLayoutParams for that.

Instead use this

RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
    (w*2)/3, 
    RelativeLayout.LayoutParams.WRAP_CONTENT
);
linLayout.setLayoutParams(lp);

or Instead of creating new LayoutParams you can reuse the existing LayoutParams of the view as shown below.

RelativeLayout.LayoutParams lp = linLayout.getLayoutParams();
lp.width  = (w*2)/3;
lp.height = RelativeLayout.LayoutParams.WRAP_CONTENT;
linLayout.setLayoutParams(lp);

回答2:

Instead of making a new LayoutParams, you should modify the existing one.

Change your code to:

button.setImageResource(R.drawable.plus_yellow);                                                                   
m = myMap.addMarker(new MarkerOptions().position(myMap.getCameraPosition().target).draggable(true));                     
LinearLayout linLayout = (LinearLayout)findViewById(R.id.lay);
LinearLayout.LayoutParams lp = linLayout.getLayoutParams();
final int left_margin = whatever;
final int top_margin = 0;
final int right_margin = whatevermore;
final int bottom_margin = 0;
lp.setMargins(left_margin, top_margin, right_margin, bottom_margin);
lp.width  = (w*2)/3;
linLayout.setLayoutParams(lp);
t = (TextView)findViewById(R.id.locinfo);                      
linLayout.setVisibility(View.VISIBLE);
t.setVisibility(View.VISIBLE);              
bIcon = true;

来源：https://stackoverflow.com/questions/15501831/add-layout-with-parameters-programmatically-android