I. Summary
Today we are going to learn about two slightly more complex widgets.
Progressbar is often used for file loading, processing, and downloading.
Listview is used to display content in the form of a list.
Final effect:
Ii. Three elements of listview:
1. listveiw is used to display the view of the list.
2. the adapter is used to map data to the mediation on the
Listview (ViewHolder reuse mechanism) for Android Performance Optimization)
I believe that most people will use the ListView control in many cases, because it is actually a lot of use, but sometimes it gets stuck when there is a lot of data, and when the ListView goes down, this requires us to optimize it.
Android ListView implements 3-level nodes (N-level extension)
The second-level node of ListView can be easily implemented by using ExpandableListView, but how to implement level 3 or even multi-level menus? Using ExpandableListView will be very cumbersome. Today we will explore another implementation method.
Idea: each time you click to expand the sub-menu, it ca
CListView can be used to display the list. CListView supports displaying the list records using a custom View template. Therefore, you can flexibly display the data table, which is a bit like the Android ListView :-). CListView supports paging and sorting. AJAX is supported for paging and sorting... syntaxHighlig CListView can be used to display the list. CListView supports displaying the list records using
The main analysis of Android ListView scrolling process caused by the image display repetition, confusion, flashing reasons and solutions, by the way to follow the ListView caching mechanism.
1. Reason Analysis
Listview Item caching mechanism: To make performance better, Listview
Today I encountered a problem:In Android, clicking listview and clicking button inside cannot take effect at the same time.
The reason is:
When the listview starts to draw, the system first calls the getcount () function to obtain the length of the listview based on its return value (this is why the length of the l
1. The effect is as follows:
The example is as follows: The add data button can be changed to a progress bar because there is no data, so I add a button to the database for testing. Generally, it takes some time to pull data from the server, so you can get a progress bar to prompt the user:
When you click the Load button, read the data from the database and append the read data to the original dataset.
Package com. exampleandroid. xiong. listviewp
more troublesome. And the accuracy is not as good as the system itself.Lazy cancer attack really do not want to do these things, so I would like to try a more speculative method, that is, in the adapter of the ListView GetView method based on position constructs a different interface, that is, assuming that position is 0, then use the original main information (micro-bo text, image) of the XML file take in
. findviewbyid (R. Id. lbllabel); imageview = (Imageview) view. findviewbyid (R. Id. IMG); lbllabel. settext (record. getlabel ()); // For demo purpose, cache is disabled here. Lazyimagehelper. LoadImage (imageview, record. getimageurl (),False); // To enable cache, simply use following code: // Lazyimagehelper. LoadImage (imageview, record. getimageurl (), true ); Return View ;}}
In the above Code, myrecord is a simple pojo class that represents a business object. It h
ListView is one of the most commonly used controls in Android. An important concept in ListView is Adapter, which serves as a bridge between controls and data sources.
Common data sources include arrays/sets (Array/List) and Cursor ).
1. obtain data from the array:
Running result:
2. obtain data from Cursor:[Html]// Get a cursor with all peopleCursor c = getConte
The final effect of the operationThe following are the specific implementations:1. Create a project named ListView2, write String.xml. The specific code is as follows:1 XML version= "1.0" encoding= "Utf-8"?>2 Resources>3 4 stringname= "App_name">ListView Examplestring>5 stringname= "Hello_world">Hello world!string>6 stringname= "Action_settings">Settingsstring>7 stringname= "Name">Namestring
Principle Analysis and Solution of control display repetition/error during Android ListView Sliding Process
Preface:
To improve the ListView performance, the most common method is to add a ViewHolder static class.
Although the performance is greatly improved, the content of the Item control is displayed repeatedly or in disorder.
Analyze and solve the following
Reprint please indicate source: http://blog.csdn.net/lmj623565791/article/details/38902805, this article from "Zhang Hongyang's Blog"1. OverviewBelieve that Android development is the most written Listview,gridview adapter, remember to develop a colleague development projects. A project down basic has been written in the ListView adapter are almost spit ~ ~ ~ Ada
PHP development framework YiiFramework tutorial (30) Zii component-ListView example
CListView can be used to display the list. CListView supports displaying the list records using a custom View template. Therefore, you can flexibly display the data table, which is a bit like the Android ListView :-).
CListView supports
Turn from: hereThe main analysis of the Android ListView scrolling process in the picture shows the repetition, confusion, flashing reasons and solutions, incidentally mention the cache mechanism of the ListView.1. Cause analysisListView Item Caching mechanism : to make the performance better, the ListView caches the r
[Android] Optimization of delayed image loading in the Adapter. getView () method of ListViewFor example, if you use the friend list as an example, each Item in ListView represents a friend. Each friend has an avatar, which needs to be loaded from the server to a local location and then displayed in the item. Obviously
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