Question

我无法弄清楚为什么ImageView不会出现在ListView

中

Left side is the result, Right side is in the editor

以下是XML代码：

`<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="wrap_content"
android:orientation="vertical">


<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/default_service_name" />

    <ImageView
        android:id="@+id/ivLed"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:adjustViewBounds="false"
        android:contentDescription="@string/ic_led"
        android:cropToPadding="false"
        android:visibility="visible"
        app:srcCompat="@mipmap/ic_led" />

    <ImageView
        android:id="@+id/ivLedDisp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:contentDescription="@string/ic_led_display"
        android:visibility="visible"
        app:srcCompat="@mipmap/ic_leddisp" />

    <ImageView
        android:id="@+id/ivSpeaker"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="top|right"
        android:contentDescription="@string/ic_speaker"
        android:foregroundGravity="top|right"
        android:visibility="visible"
        app:srcCompat="@mipmap/ic_speaker" />

    <ImageView
        android:id="@+id/ivServo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:contentDescription="@string/ic_servo"
        android:visibility="visible"
        app:srcCompat="@mipmap/ic_servo" />

    <ImageView
        android:id="@+id/ivMotor"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="top|right"
        android:contentDescription="@string/ic_motor"
        android:foregroundGravity="top|right"
        android:visibility="visible"
        app:srcCompat="@mipmap/ic_motor" />
</LinearLayout>

<TextView
    android:id="@+id/tvDesc"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:text="@string/default_service_desc" />

`

无论我使用什么图像，从哪个来源......它都没有显示...... 我试图通过代码再次使其隐藏和可见，但仍然无法工作:(

抱歉这个愚蠢的问题，但这是我第一次做Android应用程序

EDIT1：活动类 `public class ServiceList扩展了AppCompatActivity {

private ListView lvServices;
private ServiceAdaptor adaptor;
private List<Service> mServicesList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_service_list);

    FirebaseDatabase database = FirebaseDatabase.getInstance();
    DatabaseReference rootRef = database.getReference();
    DatabaseReference servicesRef = rootRef.child("services");


    lvServices = (ListView)findViewById(R.id.mListView_services);
    mServicesList = new ArrayList<>();



    servicesRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (mServicesList.size() > 0)
                mServicesList.clear();
            for (DataSnapshot id : dataSnapshot.getChildren()) {
                Service service = id.getValue(Service.class);
                mServicesList.add(service);
                Toast.makeText(getApplicationContext(), "It's WORKING!" + service, Toast.LENGTH_SHORT).show();
            }
            adaptor = new ServiceAdaptor(getApplicationContext(),mServicesList);
            lvServices.setAdapter(adaptor);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            String error = databaseError.getDetails();
        }
    });`

使用firebase，我只更改TextViews，不触及图像

EDIT2：

Service.java

public class Service {
private int id;
private String name = "Name";
private String desc = "Description";
private boolean led = false;
private boolean ledDisplay = false;
private boolean servo = false;
private boolean motor = false;
private boolean speaker = false;


public Service() {
}

//Constructors
public Service(String name, String desc, boolean led, boolean ledDisplay, boolean servo, boolean motor, boolean speaker) {
    this.name = name;
    this.desc = desc;
    this.led = led;
    this.ledDisplay = ledDisplay;
    this.servo = servo;
    this.motor = motor;
    this.speaker = speaker;
}

//Set/Get

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getDesc() {
    return desc;
}

public void setDesc(String desc) {
    this.desc = desc;
}

public boolean isLed() {
    return led;
}

public void setLed(boolean led) {
    this.led = led;
}

public boolean isLedDisplay() {
    return ledDisplay;
}

public void setLedDisplay(boolean ledDisplay) {
    this.ledDisplay = ledDisplay;
}

public boolean isServo() {
    return servo;
}

public void setServo(boolean servo) {
    this.servo = servo;
}

public boolean isMotor() {
    return motor;
}

public void setMotor(boolean motor) {
    this.motor = motor;
}

public boolean isSpeaker() {
    return speaker;
}

public void setSpeaker(boolean speaker) {
    this.speaker = speaker;
}
}

和ServiceAdaptor.java

public class ServiceAdaptor extends BaseAdapter {

private Context mContext;
private List<Service> mServicesList;

//Constructors


public ServiceAdaptor(Context mContext, List<Service> mServicesList) {
    this.mContext = mContext;
    this.mServicesList = mServicesList;
}

@Override
public int getCount() {
    return mServicesList.size();
}

@Override
public Object getItem(int position) {
    return mServicesList.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v = View.inflate(mContext, R.layout.services, null);
    TextView tvName = (TextView) v.findViewById(R.id.tvName);
    TextView tvDesc = (TextView) v.findViewById(R.id.tvDesc);
    ImageView ivLed = (ImageView) v.findViewById(R.id.ivLed);
    ImageView ivLedDisp = (ImageView) v.findViewById(R.id.ivLedDisp);
    ImageView ivServo = (ImageView) v.findViewById(R.id.ivServo);
    ImageView ivMotor = (ImageView) v.findViewById(R.id.ivMotor);
    ImageView ivSpeaker = (ImageView) v.findViewById(R.id.ivSpeaker);

    tvName.setText(mServicesList.get(position).getName());
    tvDesc.setText(mServicesList.get(position).getDesc());
    if (!mServicesList.get(position).isLed()) ivLed.setVisibility(View.INVISIBLE);
    if (!mServicesList.get(position).isLedDisplay()) ivLedDisp.setVisibility(View.INVISIBLE);
    if (!mServicesList.get(position).isServo()) ivServo.setVisibility(View.INVISIBLE);
    if (!mServicesList.get(position).isMotor()) ivMotor.setVisibility(View.INVISIBLE);
    if (!mServicesList.get(position).isSpeaker()) ivSpeaker.setVisibility(View.INVISIBLE);

    v.setTag(mServicesList.get(position).getId());

    return v;
}
}

这是他们正在接收的数据

`{  "services" : [ null, { "desc" : "Playing the speaker",
                           "led" : false,
                           "ledDisp" : false,
                           "motor" : false,
                           "name" : "Sing",
                           "servo" : false,
                           "speaker" : true},

                         { "desc" : "1322",
                           "led" : true,
                           "ledDisp" : true,
                           "motor" : false,
                           "name" : "Mike",
                           "servo" : false,
                           "speaker" : false
                          } ]
}`

只是为了检查布尔检查是否有效我改变了图像的可见性，只是改变了TextView的颜色并且有效，所以问题在于图像

Answer 1

尝试将其替换为：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="Hello, world" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@mipmap/ic_launcher"
        android:layout_toEndOf="@id/editText"/>

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@mipmap/ic_launcher"
        android:layout_toEndOf="@id/imageView"/>

</RelativeLayout>

如果它不起作用，我会给你另一个建议。

Android - ListView中的ImageView无法显示

1 个答案: