How can we create iPhone-like spinners in android?

Default spinners on the iPhone look a lot better than on Android. It looks like at least one Android app (UrbanSpoon) has been able to replicate this control, and it's awesome: http://www.urbanspoon.com/android

Anyone have any ideas on how to create this? Code would be helpful.

回答1:

If you don't need support for the trackball, then all it will take is WebView along with some minor tweaks to some existing JavaScript that impersonates Apple's UIPickerView to create applications like this.

Fancy Spinner Image http://i47.tinypic.com/aymyjc.jpg

A majority of the hard work has been done by Matteo Spinelli so start by downloading his code and then apply these changes to spinningwheel.js. His code wants to pop up the picker from the bottom of the screen with cancel and done buttons so we need to modify a few lines to eliminate this behavior.

--- spinningwheel.js.orig   2010-05-26 00:17:00.411954051 -0700
+++ spinningwheel.js    2010-05-26 00:16:32.319010720 -0700
@@ -67,12 +67,10 @@

    onOrientationChange: function (e) {
        window.scrollTo(0, 0);
-       this.swWrapper.style.top = window.innerHeight + window.pageYOffset + 'px';
        this.calculateSlotsWidth();
    },

    onScroll: function (e) {
-       this.swWrapper.style.top = window.innerHeight + window.pageYOffset + 'px';
    },

    lockScreen: function (e) {
@@ -113,9 +111,9 @@
        // Create the Spinning Wheel main wrapper
        div = document.createElement('div');
        div.id = 'sw-wrapper';
-       div.style.top = window.innerHeight + window.pageYOffset + 'px';     // Place the SW down the actual viewing screen
+       div.style.top = 0;
        div.style.webkitTransitionProperty = '-webkit-transform';
-       div.innerHTML = '<div id="sw-header"><div id="sw-cancel">Cancel</' + 'div><div id="sw-done">Done</' + 'div></' + 'div><div id="sw-slots-wrapper"><div id="sw-slots"></' + 'div></' + 'div><div id="sw-frame"></' + 'div>';
+       div.innerHTML = '<div id="sw-slots-wrapper"><div id="sw-slots"></' + 'div></' + 'div><div id="sw-frame"></' + 'div>';

        document.body.appendChild(div);

@@ -164,8 +162,6 @@
        window.addEventListener('scroll', this, true);              // Reposition SW on page scroll

        // Cancel/Done buttons events
-       document.getElementById('sw-cancel').addEventListener('touchstart', this, false);
-       document.getElementById('sw-done').addEventListener('touchstart', this, false);

        // Add scrolling to the slots
        this.swFrame.addEventListener('touchstart', this, false);
@@ -174,9 +170,6 @@
    open: function () {
        this.create();

-       this.swWrapper.style.webkitTransitionTimingFunction = 'ease-out';
-       this.swWrapper.style.webkitTransitionDuration = '400ms';
-       this.swWrapper.style.webkitTransform = 'translate3d(0, -260px, 0)';
    },


@@ -191,8 +184,6 @@

        this.swFrame.removeEventListener('touchstart', this, false);

-       document.getElementById('sw-cancel').removeEventListener('touchstart', this, false);
-       document.getElementById('sw-done').removeEventListener('touchstart', this, false);

        document.removeEventListener('touchstart', this, false);
        document.removeEventListener('touchmove', this, false);

Additionally, the index.html he provides isn't exactly what you want so replace it with this one and then copy the html, css, js, and png files into the assets directory of your project.

<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <link rel="stylesheet" href="spinningwheel.css" type="text/css" media="all" />
  <script type="text/javascript" src="spinningwheel.js?v=1.4"></script>
  <title></title>
  <script type="text/javascript">

   function getData() {
    var results = SpinningWheel.getSelectedValues();
    window.android.sendResults(results.values.join(' ')  );
   }

   function notifyAndroid() {
    window.android.readyForJavascript('');
   }

  </script>
 </head>
 <body onload="javascript:notifyAndroid()"></body>
</html>

Create an Activity that enables JavaScript in a WebView and has callbacks for it to return the selection.

public class FancySpinner extends Activity {
    private WebView webView;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ((Button) findViewById(R.id.GetSelectedTimeButton))
                .setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        webView.loadUrl("javascript:getData()");
                    }
                });
        webView = (WebView) findViewById(R.id.WebView01);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.addJavascriptInterface(new AndroidBridge(), "android");
        webView.setVerticalScrollBarEnabled(false);
        webView.loadUrl("file:///android_asset/index.html");
    }
    private class AndroidBridge {
        public void sendResults(final String arg) {
            Toast.makeText(FancySpinner.this, arg, Toast.LENGTH_SHORT).show();
        }
        public void readyForJavascript(final String arg) {
            webView.loadUrl("javascript:SpinningWheel.addSlot({ " +
                    "1: 1, 2: 2, 3: 3,  4:  4,  5:  5,  6:  6," +
                    "7: 7, 8: 8, 9: 9, 10: 10, 11: 11, 12: 12 });");
            webView.loadUrl("javascript:SpinningWheel.addSlot({ " +
                    "1: 'AM', 2: 'PM'});");
            webView.loadUrl("javascript:SpinningWheel.open();");
        }
    }
}

Finally, modify your layout so has a WebView with its height set appropriately.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" 
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:text="@string/hello" />
    <WebView 
        android:id="@+id/WebView01" 
        android:background="#77CC0000"
        android:layout_height="215dp" 
        android:layout_width="fill_parent"
        android:focusable="false" />
    <Button 
        android:text="Read Selected Time" 
        android:id="@+id/GetSelectedTimeButton" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" />
</LinearLayout>

回答2:

From the screenshot, it looks like it is just a list view with some special styling to make it look rounded. In terms of behavior, I don't think it would be any different from a ListView where the middle item is considered the selected value.