Android Development Self-study note (Android Studio) -4.5 ProgressBar and its subclasses

First, preface

ProgressBar itself represents the progress bar component, which also derives two commonly used components: Seekbar and Ratingbar, they use similar methods, but the display interface has a certain difference. Let's take a look at the instructions in the API documentation:

We can directly see ProgressBar inherit from the view class, direct subclasses have Absseekbar and contentloadingprogressbar, indirect subclasses have Ratingbar and Seekbar. Here are some ways to use these controls in turn.

Second, ProgressBar

ProgressBar is a component of the interface used to interact with users to improve user-friendliness and is typically used to show a user a time-consuming operation, to show the percentage of completion, without letting the user feel that the program is unresponsive. In the API documentation, we see that the XML attributes he supports are as follows:

XML attribute Name	Description
Android:animationresolution	Animation time-out, must be an integer value, such as "100"
Android:indeterminate	This property is set to true to indicate that the progress is not accurately displayed
Android:indeterminatebehavior	Set how to describe the reach maximum when you choose not to accurately display progress
Android:indeterminatedrawable	Sets the Drawable object that is drawn when you choose not to display the progress accurately
Android:indeterminateduration	Set the duration for which the progress is not accurately displayed
Android:indeterminateonly	Setting only shows the progress mode with no precision (state hold mode will not work)
Android:interpolator
Android:max	Set the maximum value that the progress can reach
Android:maxheight	Optional parameter sets the maximum height of the view
Android:maxwidth	Optional parameter sets the maximum width of the view
Android:minheight	Optional parameter sets the minimum height of the view
Android:minwidth	Optional parameter sets the minimum width of the view
Android:mirrorforrtl	Defines if it is necessary to reflect the relevant artboard in RTL mode, the default is False
Android:progress	Set progress values for which the progress has been completed
Android:progressdrawable	Sets the Drawable object corresponding to the progress bar track
Android:secondaryprogress	Second level progress bar, mainly used for cache usage scenarios

The form is taken from the API19 document

The progress bar supports a variety of styles, which can be set directly by setting the Style property, and the following properties are given in the API:

• Widget.ProgressBar.Horizontal  水平进度条
• Widget.ProgressBar.Small       小环形进度条
• Widget.ProgressBar.Large       大环进度条
• Widget.ProgressBar.Inverse     普通大小的环形进度条
• Widget.ProgressBar.Small.Inverse 小环形进度条
• Widget.ProgressBar.Large.Inverse 大环形进度条

另外一种使用方式就是可以使用系统的ATT属性例如：

• Style= "? Android:attr/progressbarstyle"
• Style= "? Android:attr/progressbarstylehorizontal"
• Style= "? Android:attr/progressbarstyleinverse"
• Style= "? Android:attr/progressbarstylelarge"
• Style= "? Android:attr/progressbarstylelargeinverse"
• Style= "? Android:attr/progressbarstylesmall"
• Style= "? Android:attr/progressbarstylesmallinverse"
• Style= "? Android:attr/progressbarstylesmalltitle"

For example, the following code:

For the example on Crazy handout 3, I didn't actually do it, and the custom progress bar, while following the example in the book, showed that the two icons overlapped and did not show up on the progress, and the code was as follows:

And the display effect is:

The actual running effect is also the background of the simulation thread in the update UI is not performed according to the expected results, the beginning of the show is the bottom of the red picture, has not moved, and then all the update to this overlapping picture.

Find for a long time reason also don't know where out of the problem, this problem temporarily record, wait for time to solve. (Display problem with API22 simulator)

Online to find a progress bar example, feeling is not very complete, learning is not very systematic, think of Android comes with an example of the SDK, we find it, we first look at the effect:

The location of the example is under the &androidsdk&\samples\android-19\legacy\apidemos\src\com\example\android\apis\view folder and you can see

These 4 Java files are the corresponding 4 progress bar codes.

and the corresponding layout file can go down to the upper res folder. The code is no longer attached here. Myself to find the demo, I admit this, I learned a little depressed, marked.

Third, SeekBar

Seekbar is the slider bar, which is different from the progress bar when the general progress bar is filled with color progress, while the slider bar is used to represent progress values, and allows the user to drag the slider to change the value, such as the volume adjustment of Windows:

is a sliding bar. The style of the slider is specified by the android:thumb property.

Here is a simple small example, showing that the result is to display the value of the drag slider change on the TextView.

Simple effect:

Getting the dragged value requires setting his setonseekbarchangelistener to this listener, overriding his method. The example on the right-hand side is customizing his chute, which is given in the following block.

First, the style definition (progress_drawable.xml) of the chute is given:

The following is the style layout for the sample Main page:

If you want to mimic the slider for Windows to adjust the volume, just add a imageview to the front of the internal linear layout to make the same effect.

This is the background code, mainly the implementation of the listener.

These are just the basic usage of seekbar, of course, can also be implemented in a variety of ways, the following is the Internet to see the effect of netizens:

Example Links:

1. Custom Seekbar

2.Android dynamically displays progress when using Seekbar and moves with Seekbar

3. ProgressBar or Seekbar that can display floating text hints

Iv. Ratingbar

Star rating Bar, is actually a kind of drag bar, but the difference between the drag bar is that it provides stars to indicate progress. The common properties are as follows:

Property	Description
Android:isindicator	Set whether the star rating allows the user to the table (true is not allowed to change)
Android:numstars	Set the star rating bar How many stars are there in total?
Android:rating	Set the star rating bar by default
Android:stepsize	Set the minimum number of stars to change each time

Let's do a brief example to illustrate these properties:

Also look at the effect first:

Then we give the layout file:

Where Max and progress are the properties in the progress bar, because Ratingbar itself is a special progress bar, set the maximum value is 100, 5 stars display, indicating that a star is 20, step 0.5, indicating at least half a star can be selected at a time.

Background is mainly to deal with the change when the listener.

Five, PostScript

Recent chores, learning progress slowed down, encountered problems have been stuck for a long time, some problems need to learn more in-depth, look at the SDK examples and API documentation. The following sections skip the use of some simple controls and give the location of the sample code in the SDK. No more wasted space on blogs. Accelerate your learning schedule.

Android Development Self-study note (Android Studio) -4.5 ProgressBar and its subclasses