使用
public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_flowlayout); FlowLayout flow_layout = (FlowLayout) findViewById(R.id.flow_layout); //一定要注意，我们自定义的FlowLayout中使用的是MarginLayoutParams，所以这里也只能用MarginLayoutParams，不然报ClassCastException MarginLayoutParams marginLayoutParams = new MarginLayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); int margins = (int) (2 * getResources().getDisplayMetrics().density + 0.5f); marginLayoutParams.setMargins(margins, margins, margins, margins); TextView tv1 = new TextView(new ContextThemeWrapper(this, R.style.text_style3), null, 0);//这是代码中设置style的方法！ TextView tv2 = new TextView(new ContextThemeWrapper(this, R.style.text_style2), null, 0); TextView tv3 = new TextView(new ContextThemeWrapper(this, R.style.text_style1), null, 0); TextView tv4 = new TextView(new ContextThemeWrapper(this, R.style.text_style2), null, 0); tv1.setText("代码中添加View"); tv2.setText("并设置style"); tv3.setText("并设置margins"); tv4.setText("博客：http://www.cnblogs.com/baiqiantao/，如果TextView内容特别长会是这种效果"); tv1.setLayoutParams(marginLayoutParams); tv2.setLayoutParams(marginLayoutParams); tv3.setLayoutParams(marginLayoutParams); tv4.setLayoutParams(marginLayoutParams); flow_layout.addView(tv1); flow_layout.addView(tv2); flow_layout.addView(tv3); flow_layout.addView(tv4); } }
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#E1E6F6" android:orientation="vertical" > <com.bqt.myview.FlowLayout android:id="@+id/flow_layout" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView style="@style/text_style1" android:text="包青天" /> <TextView style="@style/text_style1" android:text="流式布局" /> <TextView style="@style/text_style1" android:text="自定义ViewGroup" /> <TextView style="@style/text_style2" android:text="包青天" /> <TextView style="@style/text_style2" android:text="奋发图强" /> <TextView style="@style/text_style2" android:text="[email protected]" /> <TextView style="@style/text_style3" android:text="努力工作" /> <TextView style="@style/text_style3" android:text="月薪15K起" /> <TextView style="@style/text_style3" android:text="移动开发" /> <TextView style="@style/text_style3" android:text="android开发" /> </com.bqt.myview.FlowLayout> </LinearLayout>
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_flowlayout);
FlowLayout flow_layout = (FlowLayout) findViewById(R.id.flow_layout);
//一定要注意，我们自定义的FlowLayout中使用的是MarginLayoutParams，所以这里也只能用MarginLayoutParams，不然报ClassCastException
MarginLayoutParams marginLayoutParams = new MarginLayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
int margins = (int) (2 * getResources().getDisplayMetrics().density + 0.5f);
marginLayoutParams.setMargins(margins, margins, margins, margins);
TextView tv1 = new TextView(new ContextThemeWrapper(this, R.style.text_style3), null, 0);//这是代码中设置style的方法！
TextView tv2 = new TextView(new ContextThemeWrapper(this, R.style.text_style2), null, 0);
TextView tv3 = new TextView(new ContextThemeWrapper(this, R.style.text_style1), null, 0);
TextView tv4 = new TextView(new ContextThemeWrapper(this, R.style.text_style2), null, 0);
tv1.setText("代码中添加View");
tv2.setText("并设置style");
tv3.setText("并设置margins");
tv4.setText("博客：http://www.cnblogs.com/baiqiantao/，如果TextView内容特别长会是这种效果");
tv1.setLayoutParams(marginLayoutParams);
tv2.setLayoutParams(marginLayoutParams);
tv3.setLayoutParams(marginLayoutParams);
tv4.setLayoutParams(marginLayoutParams);
flow_layout.addView(tv1);
flow_layout.addView(tv2);
flow_layout.addView(tv3);
flow_layout.addView(tv4);
}
}
分析
简单的分析 1、对于FlowLayout，需要指定的LayoutParams，我们目前只需要能够识别margin即可，即使用MarginLayoutParams，我们需要重写ViewGroup 的几个相应的方法。 2、onMeasure中计算所有child的宽高，然后根据child的宽高，计算自己的宽和高。当然，如果不是wrap_content，直接使用父ViewGroup传入的计算值即可。 3、onLayout中对所有的childView进行布局。
onMeasure方法
- 首先得到其父容器传入的测量模式和宽高的计算值，然后遍历所有的childView，使用measureChild方法对所有的childView进行测量。
- 然后根据所有childView的测量得出的宽和高，得到该ViewGroup设置为wrap_content时的宽和高。
- 最后根据模式，如果是MeasureSpec.EXACTLY则直接使用父ViewGroup传入的宽和高，否则设置为自己计算的宽和高。
onLayout方法
- onLayout中完成对所有childView的位置以及大小的指定
- 遍历所有的childView，用于设置allViews的值，以及mLineHeight的值。
- 根据allViews的长度，遍历所有的行
- 遍历每一行的中所有的child，对child的left , top , right , bottom 进行计算和定位。
- 重置left和top，准备计算下一行的childView的位置。
View
public class FlowLayout extends ViewGroup {
/**存储所有的View，按行记录*/
private List<List<View>> mAllViews = new ArrayList<List<View>>();
/**记录每一行的最大高度*/
private List<Integer> mLineHeight = new ArrayList<Integer>();
/**布局的宽高*/
private int width = 0, height = 0;
/**每一行的宽度，width不断取其中最大的宽度*/
private int lineWidth = 0;
/**每一行的高度，累加至height*/
private int lineHeight = 0;
/**布局中的子控件*/
private View child;
/**布局中子控件设置的LayoutParam*/
private MarginLayoutParams layoutParams;
public FlowLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected LayoutParams generateLayoutParams(LayoutParams p) {
return new MarginLayoutParams(p);
}
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new MarginLayoutParams(getContext(), attrs);
}
@Override
protected LayoutParams generateDefaultLayoutParams() {
return new MarginLayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//根据所有子控件设置自己的宽和高
for (int i = 0; i < getChildCount(); i++) {
child = getChildAt(i);
// 让系统去测量当前child的宽高
measureChild(child, widthMeasureSpec, heightMeasureSpec);
// 获取当前child实际占据的宽高
layoutParams = (MarginLayoutParams) child.getLayoutParams();
int childWidth = child.getMeasuredWidth() + layoutParams.leftMargin + layoutParams.rightMargin;
int childHeight = child.getMeasuredHeight() + layoutParams.topMargin + layoutParams.bottomMargin;
//如果加入当前child后超出最大允许宽度，则将目前最大宽度给width，累加height，然后开启新行
if (lineWidth + childWidth > MeasureSpec.getSize(widthMeasureSpec)) {
width = Math.max(lineWidth, childWidth);// 对比得到最大宽度
// 开启新行，将当前行的宽高设为当前child的宽高
lineWidth = childWidth;
lineHeight = childHeight;
// 累加行高
height += lineHeight;
} else {
// 否则（不换行）累加行宽，lineHeight取最大高度
lineWidth += childWidth;
lineHeight = Math.max(lineHeight, childHeight);
}
// 如果是最后一个，则将当前记录的最大宽度和当前lineWidth做比较，并累加行高
if (i == getChildCount() - 1) {
width = Math.max(width, lineWidth);
height += lineHeight;
}
}
//如果是布局中设置的是wrap_content，设置为我们计算的值；否则，直接设置为父容器测量的值。
width = (MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY) ? MeasureSpec.getSize(widthMeasureSpec) : width;
height = (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.EXACTLY) ? MeasureSpec.getSize(heightMeasureSpec) : height;
setMeasuredDimension(width, height);
}
@SuppressLint("DrawAllocation")
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
mAllViews.clear();
mLineHeight.clear();
lineWidth = 0;
lineHeight = 0;
// 存储每一行所有的childView
List<View> lineViews = new ArrayList<View>();
for (int i = 0; i < getChildCount(); i++) {
child = getChildAt(i);
layoutParams = (MarginLayoutParams) child.getLayoutParams();
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
// 如果需要换行
if (childWidth + layoutParams.leftMargin + layoutParams.rightMargin + lineWidth > width) {
// 记录这一行所有的View中的最大高度
mLineHeight.add(lineHeight);
// 将当前行的childView保存，然后开启新的ArrayList保存下一行的childView
mAllViews.add(lineViews);
lineWidth = 0;// 重置行宽
lineViews = new ArrayList<View>();
}
//如果不需要换行，则累加
lineWidth += childWidth + layoutParams.leftMargin + layoutParams.rightMargin;
lineHeight = Math.max(lineHeight, childHeight + layoutParams.topMargin + layoutParams.bottomMargin);
lineViews.add(child);
}
// 记录最后一行
mLineHeight.add(lineHeight);
mAllViews.add(lineViews);
//记录当前child相对前一个child的坐标位置
int left = 0;
int top = 0;
// 一行一行的遍历
for (int i = 0; i < mAllViews.size(); i++) {
// 遍历每一行
lineViews = mAllViews.get(i);
for (int j = 0; j < lineViews.size(); j++) {
child = lineViews.get(j);
if (child.getVisibility() == View.GONE) continue;
layoutParams = (MarginLayoutParams) child.getLayoutParams();
//计算child的坐标
int leftPosition = left + layoutParams.leftMargin;
int topPosition = top + layoutParams.topMargin;
int rightPosition = leftPosition + child.getMeasuredWidth();
int bottomPosition = topPosition + child.getMeasuredHeight();
//对child进行布局
child.layout(leftPosition, topPosition, rightPosition, bottomPosition);
//相对位置右移
left = rightPosition + layoutParams.rightMargin;
}
//相对位置从左侧重头开始，并下移
left = 0;
top += mLineHeight.get(i);
}
}
}
样式、背景
样式 <style name="text_style1"> <item name="android:layout_width">wrap_content</item> <item name="android:layout_height">wrap_content</item> <item name="android:layout_margin">2dp</item> <item name="android:background">@drawable/flowlayout_shape1</item> <item name="android:textColor">#ffffff</item> <item name="android:paddingLeft">5dp</item> <item name="android:paddingRight">5dp</item> <item name="android:textSize">11sp</item> </style> <style name="text_style2"> <item name="android:layout_width">wrap_content</item> <item name="android:layout_height">wrap_content</item> <item name="android:layout_margin">2dp</item> <item name="android:background">@drawable/flowlayout_shape2</item> <item name="android:textColor">#880</item> <item name="android:textSize">11sp</item> </style> <style name="text_style3"> <item name="android:layout_width">wrap_content</item> <item name="android:layout_height">wrap_content</item> <item name="android:layout_margin">2dp</item> <item name="android:background">@drawable/flowlayout_shape3</item> <item name="android:textColor">#43BBE7</item> <item name="android:textSize">11sp</item> </style>
背景图 <?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" > <solid android:color="#7690A5" /> <corners android:radius="5dp" /> <padding android:bottom="2dp" android:left="2dp" android:right="2dp" android:top="2dp" /> </shape>
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" > <solid android:color="#FFFFFF" /> <corners android:radius="40dp"/> <stroke android:color="#ff0000" android:width="2dp"/> <padding android:bottom="2dp" android:left="10dp" android:right="10dp" android:top="2dp" /> </shape>
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" > <solid android:color="#C1FFC1" /> <stroke android:width="1dp" android:color="#912CEE" /> <corners android:radius="40dp" /> <padding android:bottom="2dp" android:left="10dp" android:right="10dp" android:top="2dp" /> </shape>
时间： 2024-10-23 22:04:36