android studio实现登陆和隐藏密码系列

MainActivity中的代码

package com.example.constraintlayouttest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.method.PasswordTransformationMethod;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private EditText editText;
    private CheckBox checkBox;
    private EditText editText1;

    public MainActivity() {
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button=(Button) findViewById(R.id.button5);
        editText=(EditText)findViewById(R.id.edit_text);
        checkBox=(CheckBox) findViewById(R.id.check_box);
        editText1=(EditText)findViewById(R.id.edit_text1);
        button.setOnClickListener(this);

        checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton mCompoundButton, boolean isChecked) {
                // TODO Auto-generated method stub
                if(isChecked)
                {
                    editText1.setTransformationMethod(null);
                }else editText1.setTransformationMethod(PasswordTransformationMethod.getInstance());
            }
        });
    }
    @Override
    public void onClick(View v){
        switch (v.getId()){
            case R.id.button5:
              String inputText="welcome   "+editText.getText().toString()+"!";
              Toast.makeText(MainActivity.this,inputText,Toast.LENGTH_SHORT).show();
              break;
            default:
                break;

        }
    }
}

activity_main.xml中的代码

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.example.constraintlayouttest.MainActivity"
    tools:layout_editor_absoluteY="81dp">

    <Button
        android:id="@+id/button5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="36dp"
        android:text="登陆"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="@+id/guideline" />

    <Button
        android:id="@+id/button6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="36dp"
        android:layout_marginRight="4dp"
        android:text="注册"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintRight_toRightOf="parent" />


    <android.support.constraint.Guideline
        android:id="@+id/guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.5" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="账号"
        app:layout_constraintBaseline_toBaselineOf="@+id/edit_text"
        app:layout_constraintEnd_toEndOf="@+id/textView2"
        app:layout_constraintStart_toStartOf="@+id/textView2"
        tools:text="账户" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="232dp"
        android:layout_marginStart="32dp"
        android:text="密码"
        app:layout_constraintBaseline_toBaselineOf="@+id/edit_text1"
        app:layout_constraintEnd_toStartOf="@+id/checkBox1"
        app:layout_constraintStart_toStartOf="parent"
        tools:text="密码" />

    <EditText
        android:id="@+id/edit_text"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="16dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="192dp"
        android:hint="请输入您的账号"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/edit_text1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:hint="请输入您的密码"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView2"
        app:layout_constraintTop_toBottomOf="@+id/edit_text"
        app:layout_constraintVertical_bias="0.113" />

    <CheckBox
        android:id="@+id/check_box"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="12dp"
        android:checked="false"
        android:text="显示密码"
        app:layout_constraintStart_toStartOf="@+id/edit_text1"
        app:layout_constraintTop_toBottomOf="@+id/edit_text1" />
</android.support.constraint.ConstraintLayout>

其中布局采用

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.0.0-beta1'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.android.support.constraint:constraint-layout:1.0.0-beta4'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

运行结果