近段时间在开发中遇到的一些问题的总结

1.解决安卓TextView高度和textSize大小不一致问题

在设计安卓界面的时候我发现一个TextView在布局上占用的高度和属性textSize的大小不一样，要比textSize要来的大（比如textSize="12dp"，实际的高度大概有14-16dp），仔细看的话会发现文字的上方和下发留有空白。

这个问题我纠结了很久。。。因为这严重影响布局的效果啊。不过这么基础的问题网上竟然找不到资料。。。

在安卓文档中发现一个TextView属性：android:includeFontPadding 为上标和下标留出足够的空间，以取代字体上下标.默认为真.原来是TextView默认留下了上下的padding，是为了显示上标和下标。

于是设置：android:includeFontPadding="false"，问题解决!

2.GridView实现分割线

android GridView加横竖分割线
very very easy......
给GridView加一个底色比如黑色，然后给里面的内容加另外一个底色比如白色。然后调节GridView内容的间隔透出黑色就OK了
<GridView
        android:id="@+id/gridview"
        android:background="@android:color/black" //底色为黑色
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:numColumns="2"
        android:horizontalSpacing="1dip"  //横间隔
        android:verticalSpacing="1dip"   //竖间隔
        />

2.2、定义Selector来实现


Android
GridView draw dividers

Unfortunately, after looking at the source code, I could not see any easy way to add borders other than taking the approach of adding borders to the each cell. As a reference, I will post my solution here.

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="horizontal"
    android:background="@drawable/list_selector">

    <!-- Cell contents -->

</LinearLayout>
list_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item 
        android:state_selected="true" 
        android:drawable="@drawable/item_border_selected" 
    />
    <item 
        android:state_pressed="true" 
        android:drawable="@drawable/item_border_selected" 
    />
    <item
        android:drawable="@drawable/item_border" 
    />
</selector>
item_border.xml

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid 
        android:color="@android:color/transparent" 
    />
    <stroke 
        android:width="1px" 
        android:color="@color/list_divider" 
    />
</shape>
item_border_selected.xml

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid 
        android:color="@color/list_select" 
    />
    <stroke 
        android:width="1px" 
        android:color="@color/list_divider" 
    />
</shape>
items_view.xml

<?xml version="1.0" encoding="utf-8"?>
<GridView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_marginLeft="-1px"
    android:layout_marginRight="-1px"
    android:listSelector="@android:color/transparent"
/>
Since all lines double in size as they join their neighboring cells, I made the divider size 1px instead of 1dp so it doesn't appear too large on some screens. Also, I made the grid view have negative margins to hide the lines on either side. I hope this helps someone.

21
down vote
In case you want just simple lines as borders, much, much simpler is setting a background color for a GridView and proper padding & spacing:

<GridView
    (...)
    android:background="@color/LightGold"
    android:listSelector="@android:color/transparent"
    android:horizontalSpacing="1dip"
    android:verticalSpacing="1dip"
    android:paddingLeft="1dip"
    android:paddingTop="1dip" />

public class MyGridView extends GridView { 

    public MyGridView(Context context, AttributeSet attrs) { 
        super(context, attrs); 
    } 

    public MyGridView(Context context) { 
        super(context); 
    } 

    public MyGridView(Context context, AttributeSet attrs, int defStyle) { 
        super(context, attrs, defStyle); 
    } 

    @Override 
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 

        int expandSpec = MeasureSpec.makeMeasureSpec( 
                Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST); 
        super.onMeasure(widthMeasureSpec, expandSpec); 
    } 
}

<ScrollView Android:layout_height="wrap_content" 
        Android:layout_width="fill_parent" android:id="@+id/scroll_content"> 
        <com.yourclass.MyGridView xmlns:Android="http://schemas.android.com/apk/res/android" 
            Android:id="@+id/grid_view" android:layout_width="fill_parent" 
            Android:layout_height="wrap_content" android:numColumns="auto_fit" 
            Android:horizontalSpacing="1dip" android:verticalSpacing="1dip" 
            Android:columnWidth="150dip" android:stretchMode="columnWidth" 
            Android:gravity="center"> 
             
        </com.yourclass.MyGridView> 
    </ScrollView>