android 实现文字自动滚动的走马灯效果。

红色为关键代码。

1，textview设置：

  <TextView

            android:id="@+id/tvAutoScroll"

            android:layout_width="50dp"

            android:layout_height="wrap_content"

            android:text="1222222222222222222233333333335566" 

            android:singleLine="true"

            android:scrollHorizontally="true"

            android:ellipsize="marquee"

            android:marqueeRepeatLimit="marquee_forever"

            android:layout_alignParentTop="true"

           

            />

2，代码中触发滚动：

tvAutoScroll = (TextView) findViewById(R.id.tvAutoScroll); 

tvAutoScroll.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
tvAutoScroll.setSelected(true);

}
});

二，一个简单的TabGroup控件，效果类似微信底部的tab。

package com.commonlib.ui;

import java.util.List;
import java.util.Locale;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;

public class TabGroup extends HorizontalScrollView {

private LinearLayout.LayoutParams defaultTabLayoutParams;
private LinearLayout.LayoutParams expandedTabLayoutParams;

private LinearLayout tabsContainer;

private int tabCount;

private int currentPosition = -1;
private float currentPositionOffset = 0f;

private boolean shouldExpand = true;

private int scrollOffset = 52;

private int lastScrollX = 0;

private Locale locale;

private Paint rectPaint;

public TabGroup(Context context) {
this(context, null);
}

public TabGroup(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}

public TabGroup(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
rectPaint = new Paint();
rectPaint.setAntiAlias(true);
rectPaint.setStyle(Style.FILL);
setFillViewport(true);
setWillNotDraw(false);

tabsContainer = new LinearLayout(context);
tabsContainer.setOrientation(LinearLayout.HORIZONTAL);
tabsContainer.setLayoutParams(new LayoutParams(
LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
addView(tabsContainer);

DisplayMetrics dm = getResources().getDisplayMetrics();
/**
* convert dip to pix.default.
*/
scrollOffset = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, scrollOffset, dm);

defaultTabLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
defaultTabLayoutParams.gravity = Gravity.CENTER_VERTICAL;

//
expandedTabLayoutParams = new LinearLayout.LayoutParams(0,
LayoutParams.MATCH_PARENT, 1.0f);
expandedTabLayoutParams.gravity = Gravity.CENTER_VERTICAL;

if (locale == null) {
locale = getResources().getConfiguration().locale;
}
}

public static interface OnTabItemClickListener {

void OnTabItemClick(int index);
}

private OnTabItemClickListener mOnTabItemClickListener;
private int indicatorColor = Color.BLACK;
private int indicatorHeight = 10;
private boolean isShowIndicator = false;
private int underlineHeight = 5;

public int getUnderlineHeight() {
return underlineHeight;
}

public void setUnderlineHeight(int underlineHeight) {
this.underlineHeight = underlineHeight;
invalidate();
}

public int getIndicatorColor() {
return indicatorColor;
}

public void setIndicatorColor(int indicatorColor) {
this.indicatorColor = indicatorColor;
invalidate();
}

public int getIndicatorHeight() {
return indicatorHeight;
}

public void setIndicatorHeight(int indicatorHeight) {
this.indicatorHeight = indicatorHeight;
invalidate();
}

public boolean isShowIndicator() {
return isShowIndicator;
}

public void setShowIndicator(boolean isShowIndicator) {
this.isShowIndicator = isShowIndicator;
invalidate();
}

public void setOnItemClickListener(
OnTabItemClickListener pOnTabItemClickListener) {

mOnTabItemClickListener = pOnTabItemClickListener;
}

/**
* note:all property set must call before this method.other wise,your
* property set will not be effect.
*
* @param tabItems
*/
public void setTabItems(List<TabItem> tabItems) {
if (tabItems == null || tabItems.isEmpty()) {
throw new IllegalArgumentException("tab items cannot be empty!!");
}
tabsContainer.removeAllViews();

tabCount = tabItems.size();

for (int i = 0; i < tabCount; i++) {

final TabItem item = tabItems.get(i);
final int j = i;
item.view().setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {

if (mOnTabItemClickListener != null) {
mOnTabItemClickListener.OnTabItemClick(j);
}
}
});

addTab(i, item.view());

}

getViewTreeObserver().addOnGlobalLayoutListener(
new OnGlobalLayoutListener() {

@Override
public void onGlobalLayout() {
getViewTreeObserver()
.removeGlobalOnLayoutListener(this);
scrollToChild(currentPosition, 0);
}
});

}

private void unSelectItem(int index) {
TabItem item = (TabItem) tabsContainer.getChildAt(index);
item.unselect();

}

public void selectItem(int index) {
int childcounts = tabsContainer.getChildCount();
if (index < 0 || index >= childcounts) {
return;
}
// must unselect all first.
for (int i = 0; i < childcounts; i++) {
unSelectItem(i);
}

TabItem item = (TabItem) tabsContainer.getChildAt(index);
item.select();
//
currentPosition = index;
scrollToChild(
currentPosition,
(int) (currentPositionOffset * tabsContainer.getChildAt(
currentPosition).getWidth()));

invalidate();

}

private void addTab(final int position, View tab) {
tab.setFocusable(true);
tabsContainer
.addView(tab, position, shouldExpand ? expandedTabLayoutParams
: defaultTabLayoutParams);
}

private void scrollToChild(int position, int offset) {

if (tabCount == 0) {
return;
}

int newScrollX = tabsContainer.getChildAt(position).getLeft() + offset;

if (position > 0 || offset > 0) {
newScrollX -= scrollOffset;
}

if (newScrollX != lastScrollX) {
lastScrollX = newScrollX;
scrollTo(newScrollX, 0);
}

}

public void setScrollOffset(int scrollOffsetPx) {
this.scrollOffset = scrollOffsetPx;
}

public void setShouldExpand(boolean shouldExpand) {
this.shouldExpand = shouldExpand;
}

@Override
public void onRestoreInstanceState(Parcelable state) {
SavedState savedState = (SavedState) state;
super.onRestoreInstanceState(savedState.getSuperState());
currentPosition = savedState.currentPosition;
requestLayout();
}

@Override
public Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
SavedState savedState = new SavedState(superState);
savedState.currentPosition = currentPosition;
return savedState;
}

static class SavedState extends BaseSavedState {
int currentPosition;

public SavedState(Parcelable superState) {
super(superState);
}

private SavedState(Parcel in) {
super(in);
currentPosition = in.readInt();
}

@Override
public void writeToParcel(Parcel dest, int flags) {
super.writeToParcel(dest, flags);
dest.writeInt(currentPosition);
}

public
4000
static final Creator<SavedState> CREATOR = new Creator<SavedState>() {
@Override
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}

@Override
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}

@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);

if (!isShowIndicator) {
return;
}
final int height = getHeight();
// draw underline
rectPaint.setColor(indicatorColor);
canvas.drawRect(0, height - underlineHeight, tabsContainer.getWidth(),
height, rectPaint);

// draw indicator line
rectPaint.setColor(indicatorColor);

// default: line below current tab
View currentTab = tabsContainer.getChildAt(currentPosition);
float lineLeft = currentTab.getLeft();
float lineRight = currentTab.getRight();

// if there is an offset, start interpolating left and right coordinates
// between current and next tab
if (currentPositionOffset > 0f && currentPosition < tabCount - 1) {

View nextTab = tabsContainer.getChildAt(currentPosition + 1);
final float nextTabLeft = nextTab.getLeft();
final float nextTabRight = nextTab.getRight();

lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset)
* lineLeft);
lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset)
* lineRight);
}

canvas.drawRect(lineLeft, height - indicatorHeight, lineRight, height,
rectPaint);

}

/**
* this just use for viewpager.
*
* @param position
* @param positionOffset
* @param positionOffsetPixels
*/
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {

currentPosition = position;
currentPositionOffset = positionOffset;

scrollToChild(position, (int) (positionOffset * tabsContainer
.getChildAt(position).getWidth()));

invalidate();
}

/**
* this just use for viewpager.
*
* @param state
*/
public void onPageScrollStateChanged(int state) {
final int SCROLL_STATE_IDLE = 0;
if (state == SCROLL_STATE_IDLE) {
scrollToChild(currentPosition, 0);
}

}

}

package com.commonlib.ui;

import android.view.View;

public interface TabItem {

void select();

void unselect();

View view();
}

使用示例：

tabs = (TabGroup) findViewById(R.id.main_tab_bottombar);
tabs.setOnItemClickListener(this);
List<TabItem> tabitems = new ArrayList<TabItem>();

TabItem tabIndex = new TabItemView(this, "index",
R.drawable.ic_launcher, Color.BLACK, Color.BLUE,
R.drawable.ic_launcher);
//
TabItem tabCat = new TabItemView(this, "category",
R.drawable.ic_launcher, Color.BLACK, Color.BLUE,
R.drawable.ic_launcher);
//
TabItem tabUser = new TabItemView(this, "user", R.drawable.ic_launcher,
Color.BLACK, Color.BLUE, R.drawable.ic_launcher);
//
TabItem tabSetting = new TabItemView(this, "setting",
R.drawable.ic_launcher, Color.BLACK, Color.BLUE,
R.drawable.ic_launcher);
//

tabitems.add(tabIndex);
tabitems.add(tabCat);
tabitems.add(tabUser);
tabitems.add(tabSetting);
tabs.setTabItems(tabitems);