2022-10-22学习内容

1.文本变化监听器

1.1activity_edit_hide.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="5dp">

    <EditText
        android:id="@+id/et_phone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:hint="输入11位时自动隐藏输入法"
        android:inputType="text"
        android:background="@drawable/editext_selector"
        android:maxLength="11"/>

    <EditText
        android:id="@+id/et_password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:background="@drawable/editext_selector"
        android:hint="输入6位时自动隐藏输入法"
        android:inputType="textPassword"
        android:maxLength="6"/>

</LinearLayout>

1.2ViewUtil.java

package com.example.chapter05.util;

import android.app.Activity;
import android.content.Context;
import android.view.View;
import android.view.inputmethod.InputMethodManager;

public class ViewUnil {

    public static void hideOneInputMethod(Activity act, View v) {
        // 从系统服务中获取输入法管理器
        InputMethodManager imm = (InputMethodManager) act.getSystemService(Context.INPUT_METHOD_SERVICE);
        // 关闭屏幕上的输入法软键盘
        imm.hideSoftInputFromWindow(v.getWindowToken(), 0);
    }
}

1.3EditHideActivity.java

package com.example.chapter05;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;

import com.example.chapter05.util.ViewUnil;

public class EditHideActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_edit_hide);
        EditText et_phone = findViewById(R.id.et_phone);
        EditText et_password = findViewById(R.id.et_password);

        et_phone.addTextChangedListener(new HideTextWatcher(et_phone, 11));
        et_password.addTextChangedListener(new HideTextWatcher(et_password, 6));
    }

    private class HideTextWatcher implements TextWatcher {
        // 声明一个编辑框对象
        private EditText mView;
        // 声明一个最大长度变量
        private int mMaxLength;
        public HideTextWatcher(EditText v, int maxLength) {
            this.mView = v;
            this.mMaxLength = maxLength;
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        // 在编辑框的输入文本变化后触发
        @Override
        public void afterTextChanged(Editable s) {
            // 获得已输入的文本字符串
            String str = s.toString();
            // 输入文本达到11位（如手机号），或者达到6位（如登录密码）时关闭输入法
            if (str.length() ==  mMaxLength) {
                // 隐藏输入法软键盘
                ViewUnil.hideOneInputMethod(EditHideActivity.this, mView);
            }
        }
    }
}

1.4效果：