Android UI组件

1.TextView

知识点：

• autoLink：文本自动识别为web超链接、email地址等——第五章
• AcitonBar用法：自定义ActionBar——第四章
• 创建Acticity选项菜单：让返回键在ActionBar中显示后，重写onOptionsItemSelected——第四章
• 创建，注册监听器，实现按钮功能——第四章

布局：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".TextViewActivity">

    <TextView
        android:id="@+id/tv1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:autoLink="web"
        android:text="https://www.wust.edu.cn"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.473"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.188" />

    <TextView
        android:id="@+id/tv2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:autoLink="email"
        android:text="[email protected]"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.473"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.257" />

    <TextView
        android:id="@+id/tv3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:autoLink="phone"
        android:text="+8617371998335"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.473"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.334" />

    <TextView
        android:id="@+id/tv4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:autoLink="map"
        android:text="620 Eighth Avenue New York,NY 10018"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.473"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.411" />

    <TextView
        android:id="@+id/tv5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="welcome"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.596" />

    <Button
        android:id="@+id/btn_change"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.689" />
</androidx.constraintlayout.widget.ConstraintLayout>

代码：

package com.dzh.yudemo;

import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Color;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class TextViewActivity extends AppCompatActivity {
    private Button btn;
    private TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_text_view);

        ActionBar actionBar = getSupportActionBar(); //获取ActionBar
        //actionBar.hide();  //隐藏Actionbar
        actionBar.setTitle("");  //设置标题
        actionBar.setDisplayHomeAsUpEnabled(true); //显示返回箭头

        tv = (TextView) findViewById(R.id.tv5);
        btn = (Button) findViewById(R.id.btn_change);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                tv.setText("武汉科技大学");
                tv.setTextSize(22);
                tv.setTextColor(Color.BLUE);
            }
        });
    }

    public boolean onOptionsItemSelected(@NonNull MenuItem item){
        switch (item.getItemId()){
            case android.R.id.home:
                finish();
        }
        return super.onOptionsItemSelected(item);
    }
}

2.EditText