安卓学习笔记_Day_02

女爷i 2022-04-25 00:48 264阅读 0赞

# **帧布局：** #

**每一个组件为一帧，整个布局就是每个组件一个个之间的叠加。**

<?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">
    
        <TextView
            android:id="@+id/view1"
            android:layout_gravity="center"
            android:width="320dp"
            android:height="320dp"
            android:background="#0f0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    
        <TextView
            android:id="@+id/view2"
            android:layout_gravity="center"
            android:width="280dp"
            android:height="280dp"
            android:background="#f00"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <TextView
            android:id="@+id/view3"
            android:layout_gravity="center"
            android:width="240dp"
            android:height="240dp"
            android:background="#ff0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <TextView
            android:id="@+id/view4"
            android:layout_gravity="center"
            android:width="200dp"
            android:height="200dp"
            android:background="#0ff"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <TextView
            android:id="@+id/view5"
            android:layout_gravity="center"
            android:width="160dp"
            android:height="160dp"
            android:background="#f0f"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    
        <TextView
            android:id="@+id/view6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:width="120dp"
            android:height="120dp"
            android:background="#000" />
    </FrameLayout>

实现霓虹灯效果：

public class MainActivity extends AppCompatActivity {
    
        int [] names = new int[]{
                R.id.view1, R.id.view2, R.id.view3, R.id.view4, R.id.view5, R.id.view6
        };
        TextView [] views = new TextView[names.length];
    
        class MyHandler extends Handler{
            private WeakReference<MainActivity> activity;
            public MyHandler(WeakReference<MainActivity> activity){
                this.activity = activity;
            }
    
            private int currentColor = 0;
            //定义一个颜色数组
            int[] colors = new int[]{R.color.c1,R.color.c2,R.color.c3,R.color.c4,R.color.c5,R.color.c6};
    
            @Override
            public void handleMessage(Message msg) {
    
                if(msg.what == 0x123){
            //在for循环里定义两个变量
                    for (int i = 0, len = activity.get().names.length;i< len;i++ ){
                        activity.get().views[i].setBackgroundResource(colors[(i + currentColor) % colors.length]);
                    }
                    currentColor++;
                }
                super.handleMessage(msg);
    
            }
        }
    
        private Handler handler = new MyHandler(new WeakReference<MainActivity>(this));
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            for (int i = 0; i<names.length; i++){
                views[i] = findViewById(names[i]);
            }
           new Timer().schedule(new TimerTask() {
               @Override
               public void run() {
                   handler.sendEmptyMessage(0x123);
               }
           },0,200);
        }
    }

# 遇到多个组件需要findId，可以将组件的id放置于一个数组中，将组件放置于一个数组中。通过一个for循环将二者绑定： #

int [] names = new int[]{
                R.id.view1, R.id.view2, R.id.view3, R.id.view4, R.id.view5, R.id.view6
        };
        TextView [] views = new TextView[names.length];
    
    
    
    
     for (int i = 0; i<names.length; i++){
                views[i] = findViewById(names[i]);
            }

--------------------

# 约束布局： #

相对布局的改进，有点难，先不学。

# TextView大量的XML属性： #

为文字添加图片

android:drawableRight="@mipmap/ic_launcher"

文字太长可缩略

android:ellipsize="middle"

为文字添加阴影

android:shadowColor="#0f0"
    android:shadowDx="10"
    android:shadowDy="8"
    android:shadowRadius="3"

# 用XML文件设置TextView的背景 #

xml文件

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:shape="rectangle">
    
        
        <corners android:topLeftRadius="20dp"
                android:topRightRadius="40dp"
                android:bottomRightRadius="10dp"
                android:bottomLeftRadius="60dp"/>
        
        <stroke android:width="4px"
                android:color="#f0f"/>
    
        
        <gradient
            android:startColor="#f00"
            android:centerColor="#0f0"
            android:endColor="#00f"
            android:type="sweep"/>
    </shape>

设置背景：

时钟：AnalogClock TextClock

计时器：Chronometer