1. What is a digital signature? A digital signature is a sign of your program as your own, and when someone sees the signature, they know it's relevant to you .2. Why digital signatures? The simplest and most straightforward answer: system requirements. Android requires every Android app to be digitally signed to install into the system, meaning that if an
specific values. For example:
Android: textcolor = "? Android: textdisabledcolor"
Note that this is very similar to resource reference, except that we use "? "Prefix replaces "@". When you use this tag, you provide the name of the property resource, which will be searched in the topic, so you do not need to display the Declaration type (if the Declaration, the form is?
1. What is a digital signature? A digital signature is a sign of your program as your own, and when someone sees the signature, they know it's relevant to you .2. Why digital signatures? The simplest and most straightforward answer: system requirements. Android requires every Android app to be digitally signed to install into the system, meaning that if an
topic, rather than providing specific values. For example:
Android: textcolor = "? Android: textdisabledcolor"
Note that this is very similar to resource reference, except that we use "? "Prefix replaces "@". When you use this tag, you provide the name of the property resource, which will be searched in the topic, so you do not need to display the Declaration type (if the Declaration, the form is?
words, it's useful to run Su with root, but I don't have root privileges at this point. This is the next issue to be discussed.We view the permissions of the/usr/bin/passwd file under Ubuntu, as shown in the following illustration:
The permissions of this file is more special, Linux users generally know that the file is divided into R, W, x permissions, then this s is God horse
One: The meaning of the signature:With so many people developing Android, it's entirely possible that we all put the class name, the package name, in the same name, how do you differentiate it? Signature is a distinguishing function.Since the developer may be confused by using the same package name to replace the installed program, the signature can guarantee a considerable name, but the signature of differ
Explanations of IDE, ADT, SDK, JDK, Ndk in Android1. IDE:Intelligent Development environm for short. That is, the intelligent development environment. is a development tool. Common Ides are adt-bundles and Android studio. Each of the two needs to configure the JDK.2. ADT:Short for Android development tools. That is, Android development tools. ADT is a plug-in for
For beginners, sometimes see the project will have values-v11,values-v14,values-v19 folder, there are dimens,styles and so on. What is the specific representative? I started to touch Android from 2.3, and then one day I came to more than 4.0 systems, I found a lot of V14 folders, and then understand the version of the Android API is related.VALUES-V11 represents the 11+ device on the API, using Styles.xml i
android:drawable attribute in the color_selector.xml above, Know that Android should be based on the folder to determine, in the Color folder file has the Android:color property, the file under the Drawable folder has the Android:drawable propertyIt is also important to note that the files referenced by the TextColor and background properties cannot be referenced in a random way, such as textcolor references Drawable_selector.xml,background reference
providing specific values. For example:Android:textcolor= "? Android:textdisabledcolor"Note that this is very similar to resource references, except that we use a "?" Prefix instead of "@". When you use this tag, you provide the name of the property resource, which will be looked up in the subject, so you do not need to display the declaration of that type (if the declaration is in the form of Android:attr/android:textdisabledcolor). In addition to using the identifier of this resource to query
An understanding of the four parameters (ARG) of the Onitemclicklistener listener for the adapter interface in Android development:Code: public void Onitemclick (adapterviewIf there is a ListView, the ListView contains the A,b,c,d 4 item.If you order b this item. As follows:(1) public void Onitemclick (adapterview/* The parent is equivalent to a pointer to the ListView adapter, which can be used to get everything in the ListView */(2) View view,/* Vie
the right red and green blue, so red and green blue is also known as the three primary colors, each primary color is stored the value of the information expressedTo be blunt is actually:Alpha_8 is that Alpha is made up of 8 bits .argb_4444 is made up of 4 4-bit, or 16-bit,argb_8888 is made up of 4 8-bit, or 32-bit,rgb_565 is R is 5 bits, G is 6 bits, B is 5 bits total 16 bitsThus:Alpha_8 represents a 8-bit alpha bitmapargb_4444 represents a 16-bit ARGB bitmapargb_8888 represents a 32-bit ARGB b
Why learn the callback function, and then start with the thread. Although previously wrote an article called "Android Self-learning process-multi-threading", now look still too young.In the learning thread, I tried to look at the source of handler, so the callback interface of the interest. So fill their own lack, take to learn. Stop the nonsense, organize your thoughts, and learn together.below this is a section of handler source code /** * CALLBA
Number 1th black bar position to the right covers the area when the picture is stretched vertically.The area covered by the 2nd black bar position indicates that the area is stretched only when the picture is stretched horizontallyNumber 3rd black bar position to the left covers the area where the picture is displayed vertically (mainly in the text area on the phone)No. 4th Black bar position up-covered area indicates the area where the picture is displayed horizontally (mostly text area on the
Interpolator is used to modify the animation effect, define the rate of change of the animation, can make the existing animation effect accelerated (acceleration), decelerated (deceleration), repeated (repetition), bounced (bounce) and so on.The contents of the document in Android are as follows:Acceleratedecelerateinterpolator rate changes at the beginning and end of the animation are slower, accelerating in the middleAccelerateinterpolator at the be
Meaning of onStartCommand () function return value in Android Service, androiddialog Return Value
OnStartCommand () is called by the Android system and essentially the onStart () method.
OnStartCommand () returns the following types of values:
1) START_STICKY
Explanation:
Constant to return fromonStartCommand: If this service's process is killed while it is star
; PORT: Ports + Intra-group sequence ; First angle bracket: function assignment, 0 for input, 1 for output, 2 for IO port, 6 for interrupt, rest indeterminate; The second angle bracket: built-in resistor, using 0, mark the internal resistance high impedance State, if 1 is the internal resistor pull, 2 represents the internal resistance pull down. The default state is used to indicate a resistor pull-up. Other data is invalid.; The third angle bracket: drive capability; Default rep drive capabili
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