如何在Android中创建共享按钮-Kotlin

debugcn 发表于 Dev

伦扎·波尔扎（Renza Polza）

我如何制作一个有效的共享按钮，以便可以共享某些报价
（共享文本视图中的文本）

我在网上找到了以下代码：

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

share_text_1_btn.setOnClickListener {
            val t1 = share_text_1_t.text.toString()
            val shareIntent = Intent()
            shareIntent.action = Intent.ACTION_SEND
            shareIntent.type="text/plain"
            shareIntent.putExtra(Intent.EXTRA_TEXT, t1)
            startActivity(Intent.createChooser(shareIntent,"Share via"))
        }
}

但是，当我使setOnClickListener处于活动状态时，打开片段时应用程序将崩溃，
并且没有任何红色的东西，

这些都是我的导入内容：

import android.content.ClipData
import android.content.ClipboardManager
import android.content.Intent
import android.os.Bundle
import com.google.android.material.floatingactionbutton.FloatingActionButton
import com.google.android.material.snackbar.Snackbar
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.navigateUp
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import androidx.drawerlayout.widget.DrawerLayout
import com.google.android.material.navigation.NavigationView
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.Toolbar
import android.view.Menu
import android.widget.Toast
import androidx.fragment.app.Fragment
import kotlinx.android.synthetic.main.fragment_blogs.*
import kotlinx.android.synthetic.main.fragment_share.*

import com.example.blogesther.ui.home.HomeFragment
import kotlinx.android.synthetic.main.activity_main.*
import java.util.*

这是我的xml代码：

<?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">


    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <TextView
                android:id="@+id/share_title_text"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="25dp"
                android:text="@string/share_title"
                android:textSize="50sp"
                android:textFontWeight="100"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <TextView
                android:id="@+id/share_text_1_t"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="25dp"
                android:text="@string/share_text_1"
                app:layout_constraintEnd_toStartOf="@+id/share_text_1_btn"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/share_title_text" />

            <TextView
                android:id="@+id/share_text_2_t"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="50dp"
                android:text="@string/share_text_2"
                app:layout_constraintEnd_toStartOf="@+id/share_text_2_btn"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/share_text_1_t" />

            <TextView
                android:id="@+id/share_text_3_t"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="50dp"
                android:text="@string/share_text_3"
                app:layout_constraintEnd_toStartOf="@+id/share_text_3_btn"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/share_text_2_t" />

            <TextView
                android:id="@+id/share_text_4_t"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="50dp"
                android:text="@string/share_text_4"
                app:layout_constraintEnd_toStartOf="@+id/share_text_4_btn"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/share_text_3_t" />

            <TextView
                android:id="@+id/share_text_5_t"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="50dp"
                android:text="@string/share_text_5"
                app:layout_constraintEnd_toStartOf="@+id/share_text_5_btn"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/share_text_4_t" />

            <TextView
                android:id="@+id/share_text_6_t"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="50dp"
                android:text="@string/share_text_6"
                app:layout_constraintEnd_toStartOf="@+id/share_text_6_btn"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/share_text_5_t" />

            <com.google.android.material.floatingactionbutton.FloatingActionButton
                android:id="@+id/share_text_1_btn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="50dp"
                android:clickable="true"
                android:scaleX="1"
                android:scaleY="1"
                app:layout_constraintBottom_toBottomOf="@+id/share_text_1_t"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="@+id/share_text_1_t"
                app:srcCompat="@drawable/ic_share_white_50dp" />

            <com.google.android.material.floatingactionbutton.FloatingActionButton
                android:id="@+id/share_text_2_btn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="50dp"
                android:clickable="true"
                android:scaleX="1"
                android:scaleY="1"
                app:layout_constraintBottom_toBottomOf="@+id/share_text_2_t"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="@+id/share_text_2_t"
                app:srcCompat="@drawable/ic_share_white_50dp" />

            <com.google.android.material.floatingactionbutton.FloatingActionButton
                android:id="@+id/share_text_3_btn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="50dp"
                android:clickable="true"
                android:scaleX="1"
                android:scaleY="1"
                app:layout_constraintBottom_toBottomOf="@+id/share_text_3_t"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="@+id/share_text_3_t"
                app:srcCompat="@drawable/ic_share_white_50dp" />

            <com.google.android.material.floatingactionbutton.FloatingActionButton
                android:id="@+id/share_text_4_btn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="50dp"
                android:clickable="true"
                android:scaleX="1"
                android:scaleY="1"
                app:layout_constraintBottom_toBottomOf="@+id/share_text_4_t"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="@+id/share_text_4_t"
                app:srcCompat="@drawable/ic_share_white_50dp" />

            <com.google.android.material.floatingactionbutton.FloatingActionButton
                android:id="@+id/share_text_5_btn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="50dp"
                android:clickable="true"
                android:scaleX="1"
                android:scaleY="1"
                app:layout_constraintBottom_toBottomOf="@+id/share_text_5_t"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="@+id/share_text_5_t"
                app:srcCompat="@drawable/ic_share_white_50dp" />

            <com.google.android.material.floatingactionbutton.FloatingActionButton
                android:id="@+id/share_text_6_btn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="50dp"
                android:clickable="true"
                android:scaleX="1"
                android:scaleY="1"
                app:layout_constraintBottom_toBottomOf="@+id/share_text_6_t"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="@+id/share_text_6_t"
                app:srcCompat="@drawable/ic_share_white_50dp" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    </ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>

这是logcat：

2020-03-17 12:29:03.153 28028-28028/com.example.blogesther E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.blogesther, PID: 28028
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.blogesther/com.example.blogesther.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.material.floatingactionbutton.FloatingActionButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3121)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3264)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1955)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7063)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.material.floatingactionbutton.FloatingActionButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at com.example.blogesther.MainActivity.onCreate(MainActivity.kt:50)
        at android.app.Activity.performCreate(Activity.java:7327)
        at android.app.Activity.performCreate(Activity.java:7318)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1275)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3101)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3264) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1955) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7063) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)

网络鲨鱼

尝试这个：

val share_text_1_btn = findViewById<com.google.android.material.floatingactionbutton.FloatingActionButton>(R.id.share_text_1_btn)
share_text_1_btn.setOnClickListener { 
            val intent= Intent()
            intent.action=Intent.ACTION_SEND
            intent.putExtra(Intent.EXTRA_TEXT,"Hey Check out this Great app:")
            intent.type="text/plain"
            startActivity(Intent.createChooser(intent,"Share To:"))
}

关于包含多个应用程序的隐式意图的文档

您也可以通过使用Xml onClick属性来做到这一点，只需将其添加到按钮并在错误下拉列表中自动生成函数（alt + enter）

android:onClick="shareIntent"

然后，只需将Click侦听器的内容复制到生成的函数即可。快速简便的解决方案避免了您可能会获得的大多数空指针异常。

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