Android开发学习总结day1-2

﹏ヽ暗。殇╰゛Y 2023-09-30 09:25 6阅读 0赞

### Android开发学习总结day1-2 ###

*  perface
 *  Button
 *   *  example code
     *  background problem
     *   *  resolve
     *  background image
     *  backgroundTint
     *  Button Event
     *   *  ClickEvent
         *   *  1.use Listener
             *   *  lambda
             *  2.NO Listener
         *  LongClickEvent
         *   *  1.use Listener
             *   *  lambda
         *  TouchEvent
         *   *  1. use Listener
             *   *  lambda
 *  EditText
 *   *  Attributes
     *  show result
     *  Event
 *  ImageView
 *   *  show result
     *  Attributes
     *   *  some not necessary scaleType

# perface #

In this article I will show you about button ，EditText and ImageView  
for this is the second article of the series I will not write as such detailed as the first but more detailed than other similiar article

# Button #

if we see the code we will find that button enxtends TextView which means we can use almost every attribute inTextView  
![在这里插入图片描述][3ba1f953be904c9dae51083ec5472655.png]

## example code ##

在这里插入代码片

## background problem ##

if your version is new you will find that you can’t change the background in button

### resolve ###

we can add Bridge in theme.xml to resolve this problem  
![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA566A5piO57yW56iL_size_20_color_FFFFFF_t_70_g_se_x_16]

## background image ##

background image is in the background so you can do it like this

![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA566A5piO57yW56iL_size_20_color_FFFFFF_t_70_g_se_x_16 1]  
![在这里插入图片描述][6b0c29d6d61e4b8e849f6287e329fac1.png]

![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA566A5piO57yW56iL_size_20_color_FFFFFF_t_70_g_se_x_16 2]  
![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA566A5piO57yW56iL_size_20_color_FFFFFF_t_70_g_se_x_16 3]  
![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA566A5piO57yW56iL_size_20_color_FFFFFF_t_70_g_se_x_16 4]

then wirte the code in the btn\_selector.xml

then you just need to use btn\_selector.xml in the activity\_main.xml

if you click the button you will find:  
![在这里插入图片描述][1bd678f43f7547588c6398853e56deb0.png]

## backgroundTint ##

same as background

## Button Event ##

first you should get button

private final String TAG = "btn!";
    Button btn1 = findViewById(R.id.btn1);

![在这里插入图片描述][7d355b2e380a421d814d75d7ce6065a6.png]

### ClickEvent ###

when you click the button it will happened  
by the way there have two ways to set

#### 1.use Listener ####

btn1.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Log.e(TAG, "onClick: happened");
                }
            });

##### lambda #####

btn1.setOnClickListener(view -> Log.e(TAG, "onClick: happened"));

#### 2.NO Listener ####

![在这里插入图片描述][eea8a44d49674c46b6f3a1a36db2b289.png]

public void clickEvent(View view) {
            Log.e(TAG, "clickEvent: clickEvent");
        }

### LongClickEvent ###

when you press and hold the button it will happened

#### 1.use Listener ####

btn1.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View view) {
                    Log.e(TAG, "onLongClick:happened");
                    return false;
                }
            });

##### lambda #####

btn1.setOnLongClickListener(view -> {
                Log.e(TAG, "onLongClick:happened");
                return false;
            });

### TouchEvent ###

when you touch the button it will happened

#### 1. use Listener ####

btn1.setOnTouchListener(new View.OnTouchListener() {
                @Override
                public boolean onTouch(View view, MotionEvent motionEvent) {
                    Log.e(TAG, "onTouch:happened");
                    return false;
                }
            });

##### lambda #####

btn1.setOnTouchListener((view, motionEvent) -> {
                Log.e(TAG, "onTouch:happened");
                return false;
            });

# EditText #

## Attributes ##

AttriName

explain

example

the name of the controller and you can get the controller by it’s id

android:id="@+id/text1"

hint

the text which can show by default in the controller

android:hint=“please enter your name”

background

the background of the controller you can set it with color or images

android:background="@color/teal\_200"

padding

the padding of the controller which means that the controller will have inner width

android:padding=“10dp”

textColor

the text color of the text in the controller

android:textColor="@color/purple\_500"

inputType

you can set the type that users must enter the right type or they can’t enter anything

android:inputType=“text”

drawablePadding

if you find your drawable images are close to your words you can set this attribute to make a fitness design

android:drawablePadding=“10dp”

layout\_width

the basic attribute which can set the width of the controller

android:layout\_width=“260dp”

layout\_marginLeft

that means your controller will have a outside width away to other controllers ,what’s more you can set top/bottom/right

android:layout\_marginLeft=“20dp”

drawableLeft

you can set this attribute to make sure you drawable images is in the left side,what’s more you can set top/bottom/right

android:drawableLeft="@drawable/btn\_selector"

the basic attribute which can set the width of the controller

android:layout\_height=“60dp”

## show result ##

![在这里插入图片描述][4d4423ccc9d749429c4e4f9458e36926.png]

## Event ##

we always need to get the users enter

//get edittext
            EditText viewById = findViewById(R.id.text1);
            Log.e(TAG,"EditText:"+ viewById);
    // get button
            Button btn1 = findViewById(R.id.btn1);
    // user click
            btn1.setOnClickListener(view ->{
            // get user enter
                String userInput = viewById.getText().toString();
                Log.e(TAG, "user enter => "+userInput );
    //            Log.e(TAG, "onClick: happened")
            } );

as you can see there have a button and a EditText and I write an event which if users enter something and than click the button we will get the users’ enter!  
![在这里插入图片描述][0b41e7a57af64e51bb0133ad6512e00e.png]

![在这里插入图片描述][1efeb82502ac40db9087d91e3c31021c.png]

# ImageView #

## show result ##

![在这里插入图片描述][71180d92890d4fa28c896ce3778ba0e9.png]

## Attributes ##

AttriName

explain

example

src

you can set the images by src

android:src="@drawable/btn\_selector"

scaleType

I suggest you to use “fitXY” or “fitCenter”

android:scaleType=“fitCenter”

### some not necessary scaleType ###

[3ba1f953be904c9dae51083ec5472655.png]: https://img-blog.csdnimg.cn/3ba1f953be904c9dae51083ec5472655.png
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[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA566A5piO57yW56iL_size_20_color_FFFFFF_t_70_g_se_x_16 4]: https://img-blog.csdnimg.cn/d0355369d4af424a958e6405e8f56f7a.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA566A5piO57yW56iL,size_20,color_FFFFFF,t_70,g_se,x_16
[1bd678f43f7547588c6398853e56deb0.png]: https://img-blog.csdnimg.cn/1bd678f43f7547588c6398853e56deb0.png
[7d355b2e380a421d814d75d7ce6065a6.png]: https://img-blog.csdnimg.cn/7d355b2e380a421d814d75d7ce6065a6.png
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[4d4423ccc9d749429c4e4f9458e36926.png]: https://img-blog.csdnimg.cn/4d4423ccc9d749429c4e4f9458e36926.png
[0b41e7a57af64e51bb0133ad6512e00e.png]: https://img-blog.csdnimg.cn/0b41e7a57af64e51bb0133ad6512e00e.png
[1efeb82502ac40db9087d91e3c31021c.png]: https://img-blog.csdnimg.cn/1efeb82502ac40db9087d91e3c31021c.png
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