【小白一看就会】Android UI基本组件 ——新手必看

Android UI基本组件

给大家介绍一下基本组件，会以代码加图片的形式，让新手更了解。

1.TextView和EditView

textview

<TextView
        android:id="@+id/tv_csdn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="CSDN"
        android:textColor="#000"
        android:textSize="50dp" />

private TextView textView_csdn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //绑定布局文件
        setContentView(R.layout.activity_main);
        //根据id查找组件
        textView_csdn=findViewById(R.id.textView_csdn);
      
    }

editview

<EditText
        android:id="@+id/editText_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="输入密码"
        android:background="#9595CE"
        android:textSize="40sp"
        android:drawableLeft="@mipmap/ic_launcher"
         />

2.Toast使用

layout

<Button
        android:id="@+id/bt_csdn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="欢迎来到CSDN"
        android:clickable="true"
        android:onClick="CSDN"/>

mainactivity

public void CSDN(View view) {
        //参数（上下文，要显示的文本内容，显示的时间（Toast.LENGTH_LONG、Toast.LENGTH_SHORT））
        Toast.makeText(this, "欢迎", Toast.LENGTH_SHORT).show();
    }

最终ui

3. ImageView

显示任意的图像，如一个图标。可以加载图像从不同来源，负责计算图像的测量，这样它就可以用于任何布局管理器

android:maxWidth；android:maxHeight；设置最大宽高

android:adjustViewBounds；保持宽高比

<ImageView
        android:id="@+id/tv_csdn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:maxWidth="200dp"
        android:maxHeight="200dp"
        android:adjustViewBounds="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        />

private ImageView iv_csdn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        iv_csdn = (ImageView) findViewById(R.id.iv_csdn);

    }

4.Button 和 OnClick

1.应用场景：按钮多，Java一看就懂

//....按钮多 java一看就懂
        Button btn_more_button1 = (Button) findViewById(R.id.btn_more_button1);
        Button btn_more_button2 = (Button) findViewById(R.id.btn_more_button2);
        Button btn_more_button3 = (Button) findViewById(R.id.btn_more_button3);
        btn_more_button1.setOnClickListener(this);
        btn_more_button2.setOnClickListener(this);
        btn_more_button3.setOnClickListener(this);

2.应用场景：测试用 不适合阅读

@Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_more_button1:
                Toast.makeText(this, "btn_more_button1", Toast.LENGTH_SHORT).show();
              break;
            case R.id.btn_more_button2:
                Toast.makeText(this, "btn_more_button2", Toast.LENGTH_SHORT).show();
               break;
            case R.id.btn_more_button3:
                Toast.makeText(this, "btn_more_button3", Toast.LENGTH_SHORT).show();
                break;
        }
    }
    private class MyClickListener implements View.OnClickListener{
        @Override
        public void onClick(View v) {        Toast.makeText(MainActivity.this,"innerClass",Toast.LENGTH_SHORT).show();
        }
    }
    //........................测试用 不适合阅读

3.应用场景：按钮多 强调安卓

//***********************按钮多 强调安卓
    public void clickHere(View v){
        switch (v.getId()){
            case R.id.btn1:
            Toast.makeText(this, "btn1", Toast.LENGTH_SHORT).show();
                break;
            case R.id.btn2:
            Toast.makeText(this, "btn2", Toast.LENGTH_SHORT).show();
                break;
            case R.id.btn3:
            Toast.makeText(this, "btn3", Toast.LENGTH_SHORT).show();
                break;
        }
    }

5.CheckBox和RadioButton

checkbox

layout

<CheckBox
        android:id="@+id/checkBox_java"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="java" />

    <CheckBox
        android:id="@+id/checkBox_c"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/checkBox_java"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:text="c++" />

    <CheckBox
        android:id="@+id/checkBox_python"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/checkBox_c"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:text="python" />

mainactivity

public class MainActivity extends AppCompatActivity implements CompoundButton.OnCheckedChangeListener {

    private CheckBox checkBox_java,checkBox_c,checkBox_python;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        checkBox_java=(CheckBox) findViewById(R.id.checkBox_java);
        checkBox_c=(CheckBox) findViewById(R.id.checkBox_c);
        checkBox_python=(CheckBox) findViewById(R.id.checkBox_python);

        //注册事件
        checkBox_java.setOnCheckedChangeListener(this);
        checkBox_c.setOnCheckedChangeListener(this);
        checkBox_python.setOnCheckedChangeListener(this);
    }

    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        switch (buttonView.getId()){
            case R.id.checkBox_java:
                if (isChecked){
                    Toast.makeText(this,"你选中了java",Toast.LENGTH_SHORT).show();
                }else {
                    Toast.makeText(this,"你取消了java",Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.checkBox_c:
                if (isChecked){
                    Toast.makeText(this,"你选中了c++",Toast.LENGTH_SHORT).show();
                }else {
                    Toast.makeText(this,"你取消了c++",Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.checkBox_python:
                if (isChecked){
                    Toast.makeText(this,"你选中了python",Toast.LENGTH_SHORT).show();
                }else {
                    Toast.makeText(this,"你取消了python",Toast.LENGTH_SHORT).show();
                }
                break;
        }
    }
}

RadioButton组件

先加入一个RadioGroup，再在其中设置RadioButton

<RadioGroup
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/checkBox_m"
        android:orientation="horizontal">
        <RadioButton
            android:id="@+id/radioButton_men"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="true"
            android:text="男" />

        <RadioButton
            android:id="@+id/radioButton_women"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="女" />
    </RadioGroup>