1.Android提供的五种布局有时候不能满足我们的需求，于是我要根据项目的需要自定义布局Layout；
自定义布局的步骤：
1.写一个布局CustomLayout类继承于Viewgroup类。实现onLayout（）方法；
2.把CustomLayout的包名放在一个fragmentview.xml文件中;
3.把fragmentview放到main.xml中
4.在MainActivity中setContentView(R.layout.main);
直接上图：
1.竖屏
2.横屏：
代码：1.自定义Layout类
public class CustomLayout extends ViewGroup {
private static final int UNEVEN_GRID_PENALTY_MULTIPLIER = 10;
private int mMaxChildWidth = 0;
private int mMaxChildHeight = 0;
public CustomLayout(Context context) {
super(context, null);
}
public CustomLayout(Context context, AttributeSet attrs) {
super(context, attrs, 0);
}
public CustomLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
mMaxChildWidth = 0;
mMaxChildHeight = 0;
// Measure once to find the maximum child size.
int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.AT_MOST);
int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.AT_MOST);
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() == GONE) {
continue;
}
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
mMaxChildWidth = Math.max(mMaxChildWidth, child.getMeasuredWidth());
mMaxChildHeight = Math.max(mMaxChildHeight, child.getMeasuredHeight());
}
// Measure again for each child to be exactly the same size.
childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
mMaxChildWidth, MeasureSpec.EXACTLY);
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
mMaxChildHeight, MeasureSpec.EXACTLY);
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() == GONE) {
continue;
}
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
setMeasuredDimension(
resolveSize(mMaxChildWidth, widthMeasureSpec),
resolveSize(mMaxChildHeight, heightMeasureSpec));
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int width = r - l;
int height = b - t;
final int count = getChildCount();
// Calculate the number of visible children.
int visibleCount = 0;
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() == GONE) {
continue;
}
++visibleCount;
}
if (visibleCount == 0) {
return;
}
// Calculate what number of rows and columns will optimize for even horizontal and
// vertical whitespace between items. Start with a 1 x N grid, then try 2 x N, and so on.
int bestSpaceDifference = Integer.MAX_VALUE;
int spaceDifference;
// Horizontal and vertical space between items
int hSpace = 0;
int vSpace = 0;
int cols = 1;
int rows;
while (true) {
rows = (visibleCount - 1) / cols + 1;
hSpace = ((width - mMaxChildWidth * cols) / (cols + 1));
vSpace = ((height - mMaxChildHeight * rows) / (rows + 1));
spaceDifference = Math.abs(vSpace - hSpace);
if (rows * cols != visibleCount) {
spaceDifference *= UNEVEN_GRID_PENALTY_MULTIPLIER;
}
if (spaceDifference < bestSpaceDifference) {
// Found a better whitespace squareness/ratio
bestSpaceDifference = spaceDifference;
// If we found a better whitespace squareness and there's only 1 row, this is
// the best we can do.
if (rows == 1) {
break;
}
} else {
// This is a worse whitespace ratio, use the previous value of cols and exit.
--cols;
rows = (visibleCount - 1) / cols + 1;
hSpace = ((width - mMaxChildWidth * cols) / (cols + 1));
vSpace = ((height - mMaxChildHeight * rows) / (rows + 1));
break;
}
++cols;
}
// Lay out children based on calculated best-fit number of rows and cols.
// If we chose a layout that has negative horizontal or vertical space, force it to zero.
hSpace = Math.max(0, hSpace);
vSpace = Math.max(0, vSpace);
// Re-use width/height variables to be child width/height.
width = (width - hSpace * (cols + 1)) / cols;
height = (height - vSpace * (rows + 1)) / rows;
int left, top;
int col, row;
int visibleIndex = 0;
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() == GONE) {
continue;
}
row = visibleIndex / cols;
col = visibleIndex % cols;
left = hSpace * (col + 1) + width * col;
top = vSpace * (row + 1) + height * row;
child.layout(left, top,
(hSpace == 0 && col == cols - 1) ? r : (left + width),
(vSpace == 0 && row == rows - 1) ? b : (top + height));
++visibleIndex;
}
}
}
2.xml中的引用fragment_layout.xml
<com.androidhive.dashboard.CustomLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#8B8B7A" >
<!-- News Feed Button -->
<Button
android:id="@+id/btn_news_feed"
style="@style/DashboardButton"
android:drawableTop="@drawable/btn_newsfeed"
android:text="News Feed" />
<!-- Friends Button -->
<Button
android:id="@+id/btn_friends"
style="@style/DashboardButton"
android:drawableTop="@drawable/btn_friends"
android:text="Friends" />
<!-- Messages Button -->
<Button
android:id="@+id/btn_messages"
style="@style/DashboardButton"
android:drawableTop="@drawable/btn_messages"
android:text="Messages" />
<!-- Places Button -->
<Button
android:id="@+id/btn_places"
style="@style/DashboardButton"
android:drawableTop="@drawable/btn_places"
android:text="Places" />
<!-- Events Button -->
<Button
android:id="@+id/btn_events"
style="@style/DashboardButton"
android:drawableTop="@drawable/btn_events"
android:text="Events" />
<!-- Photos Button -->
<Button
android:id="@+id/btn_photos"
style="@style/DashboardButton"
android:drawableTop="@drawable/btn_photos"
android:text="Photos" />
</com.androidhive.dashboard.CustomLayout>
3.添加到MAIN.XML
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/home_root"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!-- Include Fragmented dashboard -->
<include layout="@layout/fragment_layout"/>
</LinearLayout>
4.在MainActivity中加载
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dashboard_layout);
}
}