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先給大家展示下效果圖：
實現代碼如下：
下面簡單說下實現原理。
public class IndexBar extends LinearLayout implements View.OnTouchListener {
private static final String[] INDEXES = new String[]{"#", "A", "B", "C", "D", "E", "F", "G", "H",
"I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"};
private static final int TOUCHED_BACKGROUND_COLOR = 0x40000000;
private OnIndexChangedListener mListener;
public void setOnIndexChangedListener(OnIndexChangedListener listener) {
mListener = listener;
}
public IndexBar(Context context) {
this(context, null);
}
public IndexBar(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public IndexBar(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(attrs);
}
private void init(AttributeSet attrs) {
TypedArray ta = getContext().obtainStyledAttributes(attrs, R.styleable.IndexBar);
float indexTextSize = ta.getDimension(R.styleable.IndexBar_indexTextSize, Utils.sp2px(getContext(), 12));
int indexTextColor = ta.getColor(R.styleable.IndexBar_indexTextColor, 0xFF616161);
ta.recycle();
setOrientation(VERTICAL);
setOnTouchListener(this);
for (String index : INDEXES) {
TextView text = new TextView(getContext());
text.setText(index);
text.setTextSize(TypedValue.COMPLEX_UNIT_PX, indexTextSize);
text.setTextColor(indexTextColor);
text.setGravity(Gravity.CENTER);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 0, 1);
text.setLayoutParams(params);
addView(text);
}
}
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
setBackgroundColor(TOUCHED_BACKGROUND_COLOR);
handle(v, event);
return true;
case MotionEvent.ACTION_MOVE:
handle(v, event);
return true;
case MotionEvent.ACTION_UP:
setBackgroundColor(Color.TRANSPARENT);
handle(v, event);
return true;
}
return super.onTouchEvent(event);
}
private void handle(View v, MotionEvent event) {
int y = (int) event.getY();
int height = v.getHeight();
int position = INDEXES.length * y / height;
if (position < 0) {
position = 0;
} else if (position >= INDEXES.length) {
position = INDEXES.length - 1;
}
String index = INDEXES[position];
boolean showIndicator = event.getAction() != MotionEvent.ACTION_UP;
if (mListener != null) {
mListener.onIndexChanged(index, showIndicator);
}
}
public interface OnIndexChangedListener {
void onIndexChanged(String index, boolean showIndicator);
}
}
使用
public class CompanyActivity extends BaseActivity implements IndexBar.OnIndexChangedListener {
@Bind(R.id.lv_company)
ListView lvCompany;
@Bind(R.id.ib_indicator)
IndexBar ibIndicator;
@Bind(R.id.tv_indicator)
TextView tvIndicator;
private List<CompanyEntity> mCompanyList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_company);
// ...
}
@Override
public void onIndexChanged(String index, boolean showIndicator) {
int position = -1;
for (CompanyEntity company : mCompanyList) {
if (TextUtils.equals(company.getName(), index)) {
position = mCompanyList.indexOf(company);
break;
}
}
if (position != -1) {
lvCompany.setSelection(position);
}
tvIndicator.setText(index);
tvIndicator.setVisibility(showIndicator ? View.VISIBLE : View.GONE);
}
}
繼承自LinearLayout，添加了26個字母索引TextView，當手指滑動時通知Activity更新界面。
核心是OnTouchListener，手指滑動的時候根據當前Y坐標計算出手指所在的索引位置，要注意臨界值。
以上所述是小編給大家介紹的Android仿微信通訊錄滑動快速定位功能，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對億速云網站的支持！
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