1、引言
底部导航栏在app应用中是十分常见了，大部分的安卓应用中也都实现了底部导航栏的功能，这里我就以我以前做的一个简单小说阅读软件为例，为大家演示一下底部导航栏的使用，需要的朋友直接复制代码过去改写就行了。
2、代码实现
2.1、主界面布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical"
tools:context=".MainActivity">
<FrameLayout
android:id="@+id/fl_content"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
<RadioGroup
android:id="@+id/rg_main"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#f5f5f5"
android:gravity="center_vertical"
android:orientation="horizontal"
android:padding="3dp">
<!--书架-->
<com.kotlin.custom.DrawableRadioButton
android:id="@+id/rb_main_book"
style="@style/bottom_tag_style"
android:text="书架"
app:drawableSize="30dp"
android:clickable="true"
app:drawableTop="@drawable/book_drawable_selector" />
<!--书城-->
<com.kotlin.custom.DrawableRadioButton
android:id="@+id/rb_main_store"
style="@style/bottom_tag_style"
android:text="书城"
android:clickable="true"
app:drawableSize="30dp"
app:drawableTop="@drawable/store_drawable_selector" />
<!--我的-->
<com.kotlin.custom.DrawableRadioButton
android:id="@+id/rb_main_user"
style="@style/bottom_tag_style"
android:text="我的"
android:clickable="true"
app:drawableSize="30dp"
app:drawableTop="@drawable/user_drawable_selector" />
</RadioGroup>
</LinearLayout>2.2、主界面代码
这里包含了一些进行操作实际功能的代码，大家复制时直接忽略就行。
package com.kotlin.novel;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.fragment.app.FragmentTransaction;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.View;
import android.widget.RadioGroup;
import android.widget.Toast;
import com.google.gson.Gson;
import com.kotlin.base.BaseFragment;
import com.kotlin.data.UpdateVersion;
import com.kotlin.dialog.UpdateDialogActivity;
import com.kotlin.fragment.BookShelfFragment;
import com.kotlin.fragment.BookStoreFragment;
import com.kotlin.fragment.UserFragment;
import com.kotlin.utils.ServerUtils;
import com.kotlin.utils.SetUiSize;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
/**
* 主界面导航切换，如果需要添加界面来这里修改
*/
public class MainActivity extends FragmentActivity {
@Override
protected void onResume() {//强制竖屏
if (getRequestedOrientation()!=ActivityInfo.SCREEN_ORIENTATION_PORTRAIT){
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
super.onResume();
}
public static MainActivity activity;
public RadioGroup rg_main;
private List<BaseFragment> baseFragment;
private int position;//选中的Fragment的对应的位置
private Fragment fragment;//上次切换的Fragment
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
View decorView=getWindow().getDecorView();//获取当前界面的DecorView
int option=View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN |
View.SYSTEM_UI_FLAG_LAYOUT_STABLE |//全屏隐藏状态栏
View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR;//更改文字颜色为深黑色
decorView.setSystemUiVisibility(option);//设置系统UI元素的可见性
getWindow().setNavigationBarColor(Color.TRANSPARENT);
getWindow().setStatusBarColor(Color.TRANSPARENT);//将状态栏设置为透明色
rg_main = findViewById(R.id.rg_main);
initFragment();
setListener();
activity=this;
updateVersion();
}
private void setListener() {
rg_main.setOnCheckedChangeListener(new CheckedChangeListener());
//设置默认选中书架
rg_main.check(R.id.rb_main_book);
}
class CheckedChangeListener implements RadioGroup.OnCheckedChangeListener {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId){
case R.id.rb_main_book://书架
position = 0;
break;
case R.id.rb_main_store://书城
position = 1;
break;
case R.id.rb_main_user://我的
position = 2;
break;
}
//根据位置得到对应的Fragment
BaseFragment to = getFragment();
//替换
switchFrament(fragment,to);
}
}
/**
* @param from 刚显示的Fragment,马上就要被隐藏
* @param to 马上要切换到的Fragment，马上就要被显示
*/
private void switchFrament(Fragment from,Fragment to) {
if(from != to){
fragment = to;
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
//判断有没有被添加,才切换
if(!to.isAdded()){
//to没有被添加
//from隐藏
if(from != null){
ft.hide(from);
}
//添加to
if(to != null){
ft.add(R.id.fl_content,to).commit();
}
}else{
//to已经被添加
// from隐藏
if(from != null){
ft.hide(from);
}
//显示to
if(to != null){
ft.show(to).commit();
}
}
}
}
/**
* 根据位置得到对应的Fragment
* @return
*/
private BaseFragment getFragment() {
BaseFragment fragment = baseFragment.get(position);
return fragment;
}
private void initFragment() {
baseFragment = new ArrayList<>();
baseFragment.add(new BookShelfFragment());//书架Fragment
baseFragment.add(new BookStoreFragment());//书城Fragment
baseFragment.add(new UserFragment());//我的Fragment
}
public boolean exit;//标识是否可以退出
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
if(event.getKeyCode()==KeyEvent.KEYCODE_BACK) {
if(exit) {
BookShelfFragment.fragment.handler.sendEmptyMessage(1);//刷新书架，取消选择
return true;//不退出
}
}
return super.onKeyUp(keyCode, event);
}
private String result;
/**
* 获取更新数据
*/
private void updateVersion(){
new Thread(){
@Override
public void run() {
URL url;
try {
url=new URL(ServerUtils.updatePath);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setReadTimeout(5000);
connection.setConnectTimeout(5000);
int code = connection.getResponseCode();
if (code==200){
InputStream is = connection.getInputStream();
ByteArrayOutputStream bs=new ByteArrayOutputStream();
int len=-1;
byte[] buffer=new byte[1024];
while ((len=is.read(buffer))!=-1){
bs.write(buffer,0,len);
}
result = bs.toString();
bs.close();
is.close();
connection.disconnect();
}
} catch (Exception e) {
}
if (result!=null&&!result.equals("")){
handler.sendEmptyMessage(0);
}
}
}.start();
}
/**
* 提示
* @param message
*/
private void tip(String message){
runOnUiThread(() -> {
//更改默认Toast显示方式，需要什么直接调用方法就行
Toast toast=Toast.makeText(MainActivity.this,
message,Toast.LENGTH_SHORT);
int size= (int) (280/ SetUiSize.displayHeightDp*SetUiSize.displayHeight);
toast.setGravity(Gravity.TOP,
0,size);
toast.show();
});
}
private Handler handler=new Handler(){
@Override
public void handleMessage(@NonNull Message msg) {
super.handleMessage(msg);
switch (msg.what){
case 0:
{
UpdateVersion version = new Gson().fromJson(result, UpdateVersion.class);
if (version.getApk_version()>ServerUtils.versionCode){
Intent intent=new Intent(MainActivity.this, UpdateDialogActivity.class);
intent.putExtra("result",result);
startActivity(intent);
}
}
break;
}
}
};
}2.3、自定义控件
自定义radiobutton:
package com.kotlin.custom;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.RadioButton;
import com.kotlin.novel.R;
/**
* Describe：可控制drawableTop等图片的大小
*/
@SuppressLint("AppCompatCustomView")
public class DrawableRadioButton extends RadioButton {
private int mDrawableSize;// xml文件中设置的大小
public DrawableRadioButton(Context context) {
this(context, null, 0);
}
public DrawableRadioButton(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public DrawableRadioButton(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
Drawable drawableLeft = null, drawableTop = null, drawableRight = null, drawableBottom = null;
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.DrawableRadioButton);
int n = a.getIndexCount();
for (int i = 0; i < n; i++) {
int attr = a.getIndex(i);
switch (attr) {
case R.styleable.DrawableRadioButton_drawableSize:
mDrawableSize = a.getDimensionPixelSize(R.styleable.DrawableRadioButton_drawableSize, 50);
break;
case R.styleable.DrawableRadioButton_drawableTop:
drawableTop = a.getDrawable(attr);
break;
case R.styleable.DrawableRadioButton_drawableBottom:
drawableRight = a.getDrawable(attr);
break;
case R.styleable.DrawableRadioButton_drawableRight:
drawableBottom = a.getDrawable(attr);
break;
case R.styleable.DrawableRadioButton_drawableLeft:
drawableLeft = a.getDrawable(attr);
break;
}
}
a.recycle();
setCompoundDrawablesWithIntrinsicBounds(drawableLeft, drawableTop, drawableRight, drawableBottom);
}
/**
* RadioButton上、下、左、右设置图标
*/
public void setCompoundDrawablesWithIntrinsicBounds(Drawable left, Drawable top, Drawable right, Drawable bottom) {
if (left != null) {
left.setBounds(0, 0, mDrawableSize, mDrawableSize);
}
if (right != null) {
right.setBounds(0, 0, mDrawableSize, mDrawableSize);
}
if (top != null) {
top.setBounds(0, 0, mDrawableSize, mDrawableSize);
}
if (bottom != null) {
bottom.setBounds(0, 0, mDrawableSize, mDrawableSize);
}
setCompoundDrawables(left, top, right, bottom);
}
}
自定义圆形图标。
package com.kotlin.custom;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.*;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import com.kotlin.novel.R;
public class CircleImageView extends androidx.appcompat.widget.AppCompatImageView {
private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;
private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888;
private static final int COLORDRAWABLE_DIMENSION = 1;
private static final int DEFAULT_BORDER_WIDTH = 0;
private static final int DEFAULT_BORDER_COLOR = Color.BLACK;
private final RectF mDrawableRect = new RectF();
private final RectF mBorderRect = new RectF();
private final Matrix mShaderMatrix = new Matrix();
private final Paint mBitmapPaint = new Paint();
private final Paint mBorderPaint = new Paint();
private int mBorderColor = DEFAULT_BORDER_COLOR;
private int mBorderWidth = DEFAULT_BORDER_WIDTH;
private Bitmap mBitmap;
private BitmapShader mBitmapShader;
private int mBitmapWidth;
private int mBitmapHeight;
private float mDrawableRadius;
private float mBorderRadius;
private boolean mReady;
private boolean mSetupPending;
public CircleImageView(Context context) {
super(context);
}
public CircleImageView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
super.setScaleType(SCALE_TYPE);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.CircleImageView, defStyle, 0);
mBorderWidth = a.getDimensionPixelSize(
R.styleable.CircleImageView_border_width, DEFAULT_BORDER_WIDTH);
mBorderColor = a.getColor(R.styleable.CircleImageView_border_color,
DEFAULT_BORDER_COLOR);
a.recycle();
mReady = true;
if (mSetupPending) {
setup();
mSetupPending = false;
}
}
@Override
public ScaleType getScaleType() {
return SCALE_TYPE;
}
@Override
public void setScaleType(ScaleType scaleType) {
if (scaleType != SCALE_TYPE) {
throw new IllegalArgumentException(String.format(
"ScaleType %s not supported.", scaleType));
}
}
@Override
protected void onDraw(Canvas canvas) {
if (getDrawable() == null) {
return;
}
canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius,
mBitmapPaint);
if (mBorderWidth != 0) {
canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius,
mBorderPaint);
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
setup();
}
public int getBorderColor() {
return mBorderColor;
}
public void setBorderColor(int borderColor) {
if (borderColor == mBorderColor) {
return;
}
mBorderColor = borderColor;
mBorderPaint.setColor(mBorderColor);
invalidate();
}
public int getBorderWidth() {
return mBorderWidth;
}
public void setBorderWidth(int borderWidth) {
if (borderWidth == mBorderWidth) {
return;
}
mBorderWidth = borderWidth;
setup();
}
@Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
mBitmap = bm;
setup();
}
@Override
public void setImageDrawable(Drawable drawable) {
super.setImageDrawable(drawable);
mBitmap = getBitmapFromDrawable(drawable);
setup();
}
@Override
public void setImageResource(int resId) {
super.setImageResource(resId);
mBitmap = getBitmapFromDrawable(getDrawable());
setup();
}
private Bitmap getBitmapFromDrawable(Drawable drawable) {
if (drawable == null) {
return null;
}
if (drawable instanceof BitmapDrawable) {
return ((BitmapDrawable) drawable).getBitmap();
}
try {
Bitmap bitmap;
if (drawable instanceof ColorDrawable) {
bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION,
COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
} else {
bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(), BITMAP_CONFIG);
}
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
} catch (OutOfMemoryError e) {
return null;
}
}
private void setup() {
if (!mReady) {
mSetupPending = true;
return;
}
if (mBitmap == null) {
return;
}
mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
mBitmapPaint.setAntiAlias(true);
mBitmapPaint.setShader(mBitmapShader);
mBorderPaint.setStyle(Paint.Style.STROKE);
mBorderPaint.setAntiAlias(true);
mBorderPaint.setColor(mBorderColor);
mBorderPaint.setStrokeWidth(mBorderWidth);
mBitmapHeight = mBitmap.getHeight();
mBitmapWidth = mBitmap.getWidth();
mBorderRect.set(0, 0, getWidth(), getHeight());
mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2,
(mBorderRect.width() - mBorderWidth) / 2);
mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width()
- mBorderWidth, mBorderRect.height() - mBorderWidth);
mDrawableRadius = Math.min(mDrawableRect.height() / 2,
mDrawableRect.width() / 2);
updateShaderMatrix();
invalidate();
}
private void updateShaderMatrix() {
float scale;
float dx = 0;
float dy = 0;
mShaderMatrix.set(null);
if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width()
* mBitmapHeight) {
scale = mDrawableRect.height() / (float) mBitmapHeight;
dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
} else {
scale = mDrawableRect.width() / (float) mBitmapWidth;
dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
}
mShaderMatrix.setScale(scale, scale);
mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth,
(int) (dy + 0.5f) + mBorderWidth);
mBitmapShader.setLocalMatrix(mShaderMatrix);
}
}
自定义控件的attrs文件。
<?xml version="1.0" encoding="utf-8"?>
<resources>
<!--自定义RadioButton，增加了控制图片的功能,不要在themes文件中也加上，否则会报错-->
<declare-styleable name="DrawableRadioButton">
<attr name="drawableSize" format="dimension"/>
<attr name="drawableTop" format="reference"/>
<attr name="drawableLeft" format="reference"/>
<attr name="drawableRight" format="reference"/>
<attr name="drawableBottom" format="reference"/>
</declare-styleable>
<declare-styleable name="CircleImageView">
<attr name="border_width" format="dimension"/>
<attr name="border_color" format="color" />
</declare-styleable>
</resources>