跑馬燈效果，大家可以去原作者瀏覽https://github.com/sfsheng0322/MarqueeView
下面看自定義控件的代碼
public class MarqueeView extends ViewFlipper { private Context mContext; private List<String> notices; private boolean isSetAnimDuration = false; private OnItemClickListener onItemClickListener; private int interval = 2000; private int animDuration = 500; private int textSize = 14; private int textColor = 0xffffffff; private int gravity = Gravity.LEFT | Gravity.CENTER_VERTICAL; private static final int TEXT_GRAVITY_LEFT = 0, TEXT_GRAVITY_CENTER = 1, TEXT_GRAVITY_RIGHT = 2; public MarqueeView(Context context, AttributeSet attrs) { super(context, attrs); init(context, attrs, 0); } private void init(Context context, AttributeSet attrs, int defStyleAttr) { this.mContext = context; if (notices == null) { notices = new ArrayList<>(); } TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.MarqueeViewStyle, defStyleAttr, 0); interval = typedArray.getInteger(R.styleable.MarqueeViewStyle_mvInterval, interval); isSetAnimDuration = typedArray.hasValue(R.styleable.MarqueeViewStyle_mvAnimDuration); animDuration = typedArray.getInteger(R.styleable.MarqueeViewStyle_mvAnimDuration, animDuration); if (typedArray.hasValue(R.styleable.MarqueeViewStyle_mvTextSize)) { textSize = (int) typedArray.getDimension(R.styleable.MarqueeViewStyle_mvTextSize, textSize); textSize = DisplayUtil.px2sp(mContext, textSize); } textColor = typedArray.getColor(R.styleable.MarqueeViewStyle_mvTextColor, textColor); int gravityType = typedArray.getInt(R.styleable.MarqueeViewStyle_mvGravity, TEXT_GRAVITY_LEFT); switch (gravityType) { case TEXT_GRAVITY_CENTER: gravity = Gravity.CENTER; break; case TEXT_GRAVITY_RIGHT: gravity = Gravity.RIGHT | Gravity.CENTER_VERTICAL; break; } typedArray.recycle(); setFlipInterval(interval); Animation animIn = AnimationUtils.loadAnimation(mContext, R.anim.anim_marquee_in); if (isSetAnimDuration) animIn.setDuration(animDuration); setInAnimation(animIn); Animation animOut = AnimationUtils.loadAnimation(mContext, R.anim.anim_marquee_out); if (isSetAnimDuration) animOut.setDuration(animDuration); setOutAnimation(animOut); } // 根據公告字符串啟動輪播 public void startWithText(final String notice) { if (TextUtils.isEmpty(notice)) return; getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { @Override public void onGlobalLayout() { getViewTreeObserver().removeGlobalOnLayoutListener(this); startWithFixedWidth(notice, getWidth()); } }); } // 根據公告字符串列表啟動輪播 public void startWithList(List<String> notices) { setNotices(notices); start(); } // 根據寬度和公告字符串啟動輪播 private void startWithFixedWidth(String notice, int width) { int noticeLength = notice.length(); int dpW = DisplayUtil.px2dip(mContext, width); int limit = dpW / textSize; if (dpW == 0) { throw new RuntimeException("Please set MarqueeView width !"); } if (noticeLength <= limit) { notices.add(notice); } else { int size = noticeLength / limit + (noticeLength % limit != 0 ? 1 : 0); for (int i = 0; i < size; i++) { int startIndex = i * limit; int endIndex = ((i + 1) * limit >= noticeLength ? noticeLength : (i + 1) * limit); notices.add(notice.substring(startIndex, endIndex)); } } start(); } // 啟動輪播 public boolean start() { if (notices == null || notices.size() == 0) return false; removeAllViews(); for (int i = 0; i < notices.size(); i++) { final TextView textView = createTextView(notices.get(i), i); final int finalI = i; textView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if (onItemClickListener != null) { onItemClickListener.onItemClick(finalI, textView); } } }); addView(textView); } if (notices.size() > 1) { startFlipping(); } return true; } // 創建ViewFlipper下的TextView private TextView createTextView(String text, int position) { TextView tv = new TextView(mContext); tv.setGravity(gravity); tv.setText(text); tv.setTextColor(textColor); tv.setTextSize(textSize); tv.setTag(position); return tv; } public int getPosition() { return (int) getCurrentView().getTag(); } public List<String> getNotices() { return notices; } public void setNotices(List<String> notices) { this.notices = notices; } public void setOnItemClickListener(OnItemClickListener onItemClickListener) { this.onItemClickListener = onItemClickListener; } public interface OnItemClickListener { void onItemClick(int position, TextView textView); }}跑馬燈view是繼承ViewFlipper，可以看到他的結構體
其實ViewFlipper工作機制很簡單，如上圖，就是將添加到ViewFlipper中的子View按照順序定時的顯示是其中一個子View，其他的子View設置為Gone狀態
private Context mContext; private List<String> notices; private boolean isSetAnimDuration = false; private OnItemClickListener onItemClickListener; private int interval = 2000; private int animDuration = 500; private int textSize = 14; private int textColor = 0xffffffff; private int gravity = Gravity.LEFT | Gravity.CENTER_VERTICAL; private static final int TEXT_GRAVITY_LEFT = 0, TEXT_GRAVITY_CENTER = 1, TEXT_GRAVITY_RIGHT = 2;
看出view的一些屬性，上下文，集合，是否動畫延遲，點擊事件，跑馬燈的時間間隔，動畫延遲時間，字體大小顏色，設置位置在靠左垂直中間對齊，文字的位置常量。
修改MarqueeView的構造方法，我們可以在右鍵generate快速生成。
<declare-styleable name="MarqueeViewStyle"> <attr name="mvInterval" format="integer|reference"/> <attr name="mvAnimDuration" format="integer|reference"/> <attr name="mvTextSize" format="dimension|reference"/> <attr name="mvTextColor" format="color|reference"/> <attr name="mvGravity"> <enum name="left" value="0"/> <enum name="center" value="1"/> <enum name="right" value="2"/> </attr> </declare-styleable>
TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.MarqueeViewStyle, defStyleAttr, 0);
首先獲取屬性集合，獲取一個mv的間隔，默認值2000
isSetAnimDuration = typedArray.hasValue(R.styleable.MarqueeViewStyle_mvAnimDuration);
是否設置動畫時間的延遲
if (typedArray.hasValue(R.styleable.MarqueeViewStyle_mvTextSize)) { textSize = (int) typedArray.getDimension(R.styleable.MarqueeViewStyle_mvTextSize, textSize); textSize = DisplayUtil.px2sp(mContext, textSize); }假如設置有自定義文字大小，就獲取然后px轉成sp
獲取控件位置，自由設置
在后面要回收
typedArray.recycle();
setFlipInterval(interval);設置滾屏間隔，單位毫秒
Animation animIn = AnimationUtils.loadAnimation(mContext, R.anim.anim_marquee_in); if (isSetAnimDuration) animIn.setDuration(animDuration); setInAnimation(animIn); Animation animOut = AnimationUtils.loadAnimation(mContext, R.anim.anim_marquee_out); if (isSetAnimDuration) animOut.setDuration(animDuration); setOutAnimation(animOut);
一進一出的動畫效果
// 根據公告字符串啟動輪播
public void startWithText(final String notice)
暴露個公共方法，里面有測量view的getViewTreeObserver方法，里面內部類調用了startWithFixedWidth(notice, getWidth());方法
// 根據寬度和公告字符串啟動輪播 private void startWithFixedWidth(String notice, int width) { int noticeLength = notice.length(); int dpW = DisplayUtil.px2dip(mContext, width); int limit = dpW / textSize; if (dpW == 0) { throw new RuntimeException("Please set MarqueeView width !"); } if (noticeLength <= limit) { notices.add(notice); } else { int size = noticeLength / limit + (noticeLength % limit != 0 ? 1 : 0); for (int i = 0; i < size; i++) { int startIndex = i * limit; int endIndex = ((i + 1) * limit >= noticeLength ? noticeLength : (i + 1) * limit); notices.add(notice.substring(startIndex, endIndex)); } } start(); }轉換得到一個dp的寬度，限制字數長度大小。假如字符串小于直接add。假如過長取余得到行數。然后循環，獲取那行的頭尾，末尾假如2行字數還是比總體長度大就取總體長度，假如小于總體長度，就取那行的末尾下表。
然后開始播放
// 啟動輪播 public boolean start() { if (notices == null || notices.size() == 0) return false; removeAllViews(); for (int i = 0; i < notices.size(); i++) { final TextView textView = createTextView(notices.get(i), i); final int finalI = i; textView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if (onItemClickListener != null) { onItemClickListener.onItemClick(finalI, textView); } } }); addView(textView); } if (notices.size() > 1) { startFlipping(); } return true; }創建部署每行的tv
// 創建ViewFlipper下的TextView private TextView createTextView(String text, int position) { TextView tv = new TextView(mContext); tv.setGravity(gravity); tv.setText(text); tv.setTextColor(textColor); tv.setTextSize(textSize); tv.setTag(position); return tv; }然后將所有的textview add起來，然后開始播放。后面就是做個點擊回調，然后set get這個公告的集合。
最后不要忘了在布局頂層加入
xmlns:app="http://schemas.android.com/apk/res-auto"
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。
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