您好,登錄后才能下訂單哦!
小編給大家分享一下如何利用Android從0到1實(shí)現(xiàn)一個流布局控件,希望大家閱讀完這篇文章之后都有所收獲,下面讓我們一起去探討吧!
流布局在在項(xiàng)目中還是會時不時地用到的,比如在搜索歷史記錄,分類,熱門詞語等可用標(biāo)簽來顯示的,都可以設(shè)計(jì)成流布局的展示方式。這里我從0到1實(shí)現(xiàn)了一個搜索歷史記錄的流布局。
1、創(chuàng)建FlowLayoutView,創(chuàng)建數(shù)據(jù)源,并添加各個子view。
2、在onMeasure方法中遍歷子view,通過簡單計(jì)算剩余寬度,用集合存儲當(dāng)前行的幾個子view,再根據(jù)子view的累加高度設(shè)置自己的最終尺寸。
3、在onLayout方法中,遍歷每一行,遍歷該行的子view,依次調(diào)動layout設(shè)置子view位置。
引入行的概念,每一行存儲自己應(yīng)該放置的子view。判斷該行剩余空間和該子view的寬度,來決定能放入該行,還是需要新建下一行來存儲。
主要代碼:
/** * description 流布局viewGroup */ public class FlowLayoutView extends ViewGroup { private List<Row> rows = new ArrayList<>(); private int usedWidth; /** * 當(dāng)前需要操作的行 */ private Row curRow; private int verticalPadding = 30; private int horizontalPadding = 40; public FlowLayoutView(Context context) { super(context); } public FlowLayoutView(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { restoreLine(); //每次重新布局,屬性要初始化,避免onMeasure重復(fù)調(diào)用混亂問題 //子view設(shè)置寬高為父view大小減去padding值 int width = MeasureSpec.getSize(widthMeasureSpec); int height = MeasureSpec.getSize(heightMeasureSpec); int widthMode = MeasureSpec.getMode(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); //設(shè)置每個子view寬高,并且將每個子View歸到自己的行 for (int i = 0; i < getChildCount(); i++) { View childView = getChildAt(i); //設(shè)置子view設(shè)置AT_MOST模式,即布局屬性為wrap_content int childWidthSpec = MeasureSpec.makeMeasureSpec(width, widthMode == MeasureSpec.EXACTLY ? MeasureSpec.AT_MOST : widthMode); int childHeightSpec = MeasureSpec.makeMeasureSpec(height, heightMode == MeasureSpec.EXACTLY ? MeasureSpec.AT_MOST : heightMode); childView.measure(childWidthSpec, childHeightSpec); if (curRow == null) { curRow = new Row(); } //根據(jù)當(dāng)前childview寬度和剩余寬度判斷是否能放進(jìn)當(dāng)前行,放不了就要換行 if (childView.getMeasuredWidth() + horizontalPadding > width - usedWidth) { //先換行,再放入 nextLine(); } usedWidth += childView.getMeasuredWidth() + horizontalPadding; curRow.addView(childView); } //將最后一個row加入到rows中 rows.add(curRow); //根據(jù)子view組成的高度重設(shè)自己高度 int finalHeight = 0; for (Row row : rows) { finalHeight += row.height + verticalPadding; } setMeasuredDimension(width, finalHeight); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int top = 0; //遍歷每一行,將每一行子view布局 for (Row row : rows) { row.layout(top); top = top + row.height + verticalPadding; } } /** * 換行,需要將當(dāng)前row存儲,并且創(chuàng)建新的row,新的行使用空間置0 */ private void nextLine() { rows.add(curRow); curRow = new Row(); usedWidth = 0; } /** * 每次onmeasure需要重置信息 */ private void restoreLine() { rows.clear(); curRow = new Row(); usedWidth = 0; } /** * 用于記錄每一行放置子View的信息 */ class Row { /** * 該行放置的子view */ private List<View> childViews = new ArrayList<>(); private int height; public void addView(View view) { childViews.add(view); height = view.getMeasuredHeight() > height ? view.getMeasuredHeight() : height; //高度取最高子view的高度 } public int getSize() { return childViews.size(); } /** * 將當(dāng)前childViews進(jìn)行布局 * top 當(dāng)前hang處于的頂部高度 */ public void layout(int top) { int leftMargin = 0; for (int i = 0; i < childViews.size(); i++) { View view = childViews.get(i); view.layout(leftMargin, top, leftMargin + view.getMeasuredWidth(), top + view.getMeasuredHeight()); leftMargin = leftMargin + view.getMeasuredWidth() + horizontalPadding; } } } }
MainActivity代碼:
public class MainActivity extends AppCompatActivity { private FlowLayoutView flowLayoutView; private String[] tagTextArray = new String[]{"天貓精靈", "充電臺燈", "睡衣", "手表", "創(chuàng)意水杯", "夏天T恤男", "燈光機(jī)械鍵盤", "計(jì)算機(jī)原理", "學(xué)霸筆記本", "可口可樂", "跑步機(jī)", "旅行箱", "竹漿衛(wèi)生紙", "吹風(fēng)機(jī)", "洗面奶", "窗簾"}; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); } private void init() { flowLayoutView = findViewById(R.id.flowlayout); TextView tvAddTag = findViewById(R.id.tv_addtag); tvAddTag.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { View view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.item_tagview, null); TextView tvContent = view.findViewById(R.id.tv_content); tvContent.setText(tagTextArray[(int) (Math.random()*tagTextArray.length)]); flowLayoutView.addView(view); } }); } }
看完了這篇文章,相信你對“如何利用Android從0到1實(shí)現(xiàn)一個流布局控件”有了一定的了解,如果想了解更多相關(guān)知識,歡迎關(guān)注億速云行業(yè)資訊頻道,感謝各位的閱讀!
免責(zé)聲明:本站發(fā)布的內(nèi)容(圖片、視頻和文字)以原創(chuàng)、轉(zhuǎn)載和分享為主,文章觀點(diǎn)不代表本網(wǎng)站立場,如果涉及侵權(quán)請聯(lián)系站長郵箱:is@yisu.com進(jìn)行舉報,并提供相關(guān)證據(jù),一經(jīng)查實(shí),將立刻刪除涉嫌侵權(quán)內(nèi)容。