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Android新手开发之旅目录
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第一步:自定义view继承ViewGroup
[Java] 纯文本查看 复制代码 import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.List;
public class FlowLayout extends ViewGroup {
public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public FlowLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public FlowLayout(Context context) {
this(context, null);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
int modeHeight = MeasureSpec.getMode(heightMeasureSpec);
// 如果是warp_content情况下,记录宽和高
int width = 0;
int height = 0;
// 记录每一行的宽度与高度
int lineWidth = 0;
int lineHeight = 0;
// 得到内部元素的个数
int cCount = getChildCount();
for (int i = 0; i < cCount; i++) {
// 通过索引拿到每一个子view
View child = getChildAt(i);
// 测量子View的宽和高,系统提供的measureChild
measureChild(child, widthMeasureSpec, heightMeasureSpec);
// 得到LayoutParams
MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();
// 子View占据的宽度
int childWidth = child.getMeasuredWidth() + lp.leftMargin
+ lp.rightMargin;
// 子View占据的高度
int childHeight = child.getMeasuredHeight() + lp.topMargin
+ lp.bottomMargin;
// 换行 判断 当前的宽度大于 开辟新行
if (lineWidth + childWidth > sizeWidth - getPaddingLeft() - getPaddingRight()) {
// 对比得到最大的宽度
width = Math.max(width, lineWidth);
// 重置lineWidth
lineWidth = childWidth;
// 记录行高
height += lineHeight;
lineHeight = childHeight;
} else
// 未换行
{
// 叠加行宽
lineWidth += childWidth;
// 得到当前行最大的高度
lineHeight = Math.max(lineHeight, childHeight);
}
// 特殊情况,最后一个控件
if (i == cCount - 1) {
width = Math.max(lineWidth, width);
height += lineHeight;
}
}
setMeasuredDimension(
modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width + getPaddingLeft() + getPaddingRight(),
modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height + getPaddingTop() + getPaddingBottom()//
);
}
/**
* 存储所有的View
*/
private List<List<View>> mAllViews = new ArrayList<List<View>>();
/**
* 每一行的高度
*/
private List<Integer> mLineHeight = new ArrayList<Integer>();
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
mAllViews.clear();
mLineHeight.clear();
// 当前ViewGroup的宽度
int width = getWidth();
int lineWidth = 0;
int lineHeight = 0;
// 存放每一行的子view
List<View> lineViews = new ArrayList<View>();
int cCount = getChildCount();
for (int i = 0; i < cCount; i++) {
View child = getChildAt(i);
MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
// 如果需要换行
if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width - getPaddingLeft() - getPaddingRight()) {
// 记录LineHeight
mLineHeight.add(lineHeight);
// 记录当前行的Views
mAllViews.add(lineViews);
// 重置我们的行宽和行高
lineWidth = 0;
lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
// 重置我们的View集合
lineViews = new ArrayList<View>();
}
lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
lineHeight = Math.max(lineHeight, childHeight + lp.topMargin
+ lp.bottomMargin);
lineViews.add(child);
}// for end
// 处理最后一行
mLineHeight.add(lineHeight);
mAllViews.add(lineViews);
// 设置子View的位置
int left = getPaddingLeft();
int top = getPaddingTop();
// 行数
int lineNum = mAllViews.size();
for (int i = 0; i < lineNum; i++) {
// 当前行的所有的View
lineViews = mAllViews.get(i);
lineHeight = mLineHeight.get(i);
for (int j = 0; j < lineViews.size(); j++) {
View child = lineViews.get(j);
// 判断child的状态
if (child.getVisibility() == View.GONE) {
continue;
}
MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();
int lc = left + lp.leftMargin;
int tc = top + lp.topMargin;
int rc = lc + child.getMeasuredWidth();
int bc = tc + child.getMeasuredHeight();
// 为子View进行布局
child.layout(lc, tc, rc, bc);
left += child.getMeasuredWidth() + lp.leftMargin
+ lp.rightMargin;
}
left = getPaddingLeft();
top += lineHeight;
}
}
/**
* 与当前ViewGroup对应的LayoutParams
*/
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new MarginLayoutParams(getContext(), attrs);
}
}
第二步:在布局中使用自定义的view
[XML] 纯文本查看 复制代码 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.company.test.FlowLayout
android:id="@+id/fl"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
第三步:每个item的布局
[XML] 纯文本查看 复制代码 <?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_margin="8dp"
android:padding="5dp"
android:background="@drawable/bg_flowlayout"
android:textColor="@color/colorPrimary"
android:textSize="14sp" />
bg_flowlayout:
[XML] 纯文本查看 复制代码 <?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="3dp" />
<stroke
android:width="0.5dp"
android:color="@color/colorPrimary" />
</shape>
第四步:
[Java] 纯文本查看 复制代码 import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private FlowLayout mFlowLayout;
private String[] data = {"Java", "Android", "Ios", "前端", "C++", "软件工程师","高级工程师","数据库开发","项目经理","美工","PHP","数据分析","网络工程师","网站编辑","Go"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
mFlowLayout = (FlowLayout) findViewById(R.id.fl);
for (int i = 0; i < data.length; i++) {
TextView tv = (TextView) LayoutInflater.from(this).inflate(R.layout.item_flowlayout, mFlowLayout, false);
tv.setText(data[i]);
mFlowLayout.addView(tv);
final int finalI = i;
tv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "你点击了" + data[finalI], Toast.LENGTH_SHORT).show();
}
});
}
}
}
运行效果:
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